diff --git a/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.readsession-1.json b/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.readsession-1.json
index 1b0aad90967..ddd2bfb0c6a 100644
--- a/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.readsession-1.json
+++ b/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.readsession-1.json
@@ -22,41 +22,6 @@
       "status": "ready",
       "transcriptLoading": false
     },
-    "1821d5c2646a": {
-      "name": "nativeChat.readSession#1",
-      "ordinal": 2,
-      "args": [
-        {
-          "name": "method",
-          "value": "nativeChat.readSession"
-        },
-        {
-          "name": "params",
-          "value": {
-            "agent": "claude",
-            "beforeOffset": 1200,
-            "limit": 60,
-            "sessionId": "session-1",
-            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
-          }
-        },
-        {
-          "name": "options",
-          "value": {
-            "$rpc": "absent"
-          }
-        }
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-      "settlement": {
-        "status": "fulfilled",
-        "startedAt": 0,
-        "settledAt": 0,
-        "value": {
-          "id": "frame-2",
-          "ok": true
-        }
-      }
-    },
     "197fa03857dd": {
       "crash": {
         "$rpc": "null"
@@ -70,95 +35,17 @@
       "status": "ready",
       "transcriptLoading": false
     },
-    "2dd353a0e048": {
-      "name": "nativeChat.readSession#1",
-      "ordinal": 2,
-      "args": [
-        {
-          "name": "method",
-          "value": "nativeChat.readSession"
-        },
-        {
-          "name": "params",
-          "value": {
-            "agent": "claude",
-            "beforeOffset": 1200,
-            "limit": 60,
-            "sessionId": "session-1",
-            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
-          }
-        },
-        {
-          "name": "options",
-          "value": {
-            "$rpc": "absent"
-          }
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-      "settlement": {
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-        "settledAt": 0,
-        "value": {
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-            "code": "refused",
-            "message": ""
-          },
-          "id": "frame-2",
-          "ok": false
-        }
-      }
-    },
     "3e14b1ec5bde": {
       "name": "nativeChat.unsubscribe#2",
       "ordinal": 6,
       "json": "{\"id\":\"frame-5\",\"deviceToken\":\"recording-device\",\"method\":\"nativeChat.unsubscribe\",\"params\":{\"subscriptionId\":\"claude:session-1:00000000-0000-4000-8000-000000000001\"}}"
     },
-    "41f222acdcb2": {
-      "name": "nativeChat.readSession#1",
-      "ordinal": 2,
-      "args": [
-        {
-          "name": "method",
-          "value": "nativeChat.readSession"
-        },
-        {
-          "name": "params",
-          "value": {
-            "agent": "claude",
-            "beforeOffset": 1200,
-            "limit": 60,
-            "sessionId": "session-1",
-            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
-          }
-        },
-        {
-          "name": "options",
-          "value": {
-            "$rpc": "absent"
-          }
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-      "settlement": {
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-        "startedAt": 0,
-        "settledAt": 0,
-        "value": {
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-            "message": "outer refused"
-          },
-          "id": "frame-2",
-          "ok": false
-        }
-      }
-    },
     "456781b97acc": {
       "name": "nativeChat.subscribe#1",
       "ordinal": 1,
       "json": "{\"id\":\"frame-1\",\"deviceToken\":\"recording-device\",\"method\":\"nativeChat.subscribe\",\"params\":{\"agent\":\"claude\",\"sessionId\":\"session-1\",\"limit\":40,\"subscriptionId\":\"claude:session-1:00000000-0000-4000-8000-000000000001\",\"capabilities\":{\"transcriptPending\":1},\"transcriptPath\":\"/work/feature/.claude/session-1.jsonl\"}}"
     },
-    "63d9cc126261": {
+    "65ff352ca953": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -179,7 +66,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -189,7 +77,7 @@
         "settledAt": 0,
         "error": {
           "category": "Error",
-          "message": "transport failure",
+          "message": "",
           "isRpcDeliveryUnknown": true
         }
       }
@@ -199,6 +87,42 @@
       "ordinal": 4,
       "json": "{\"id\":\"frame-3\",\"deviceToken\":\"recording-device\",\"method\":\"nativeChat.subscribe\",\"params\":{\"agent\":\"claude\",\"sessionId\":\"session-1\",\"limit\":40,\"subscriptionId\":\"claude:session-1:00000000-0000-4000-8000-000000000001\",\"capabilities\":{\"transcriptPending\":1},\"transcriptPath\":\"/work/feature/.claude/session-1.jsonl\"}}"
     },
+    "75842f212e52": {
+      "name": "nativeChat.readSession#1",
+      "ordinal": 2,
+      "args": [
+        {
+          "name": "method",
+          "value": "nativeChat.readSession"
+        },
+        {
+          "name": "params",
+          "value": {
+            "agent": "claude",
+            "beforeOffset": 1200,
+            "limit": 60,
+            "sessionId": "session-1",
+            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
+          }
+        },
+        {
+          "name": "options",
+          "value": {
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
+          }
+        }
+      ],
+      "settlement": {
+        "status": "fulfilled",
+        "startedAt": 0,
+        "settledAt": 0,
+        "value": {
+          "id": "frame-2",
+          "ok": true
+        }
+      }
+    },
     "7b237e9824c8": {
       "crash": {
         "$rpc": "null"
@@ -225,61 +149,12 @@
       "status": "ready",
       "transcriptLoading": false
     },
-    "7ee0fd6f2bd8": {
-      "name": "nativeChat.readSession#1",
-      "ordinal": 2,
-      "args": [
-        {
-          "name": "method",
-          "value": "nativeChat.readSession"
-        },
-        {
-          "name": "params",
-          "value": {
-            "agent": "claude",
-            "beforeOffset": 1200,
-            "limit": 60,
-            "sessionId": "session-1",
-            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
-          }
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-        "settledAt": 0,
-        "error": {
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-          "message": "",
-          "isRpcDeliveryUnknown": true
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     "7eedfcf76fd3": {
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       "ordinal": 5,
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     },
-    "8f91342d7840": {
-      "crash": {
-        "$rpc": "null"
-      },
-      "error": {
-        "$rpc": "null"
-      },
-      "hasMore": false,
-      "loadingEarlier": false,
-      "messageIds": ["m-1", "m-2", "m-3", "m-4", "m-5"],
-      "status": "ready",
-      "transcriptLoading": false
-    },
-    "9a114b6ce2df": {
+    "81eaceac1130": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -300,7 +175,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -309,15 +185,16 @@
         "startedAt": 0,
         "settledAt": 0,
         "value": {
+          "error": {
+            "code": "refused",
+            "message": "outer refused"
+          },
           "id": "frame-2",
-          "ok": true,
-          "result": {
-            "error": "refused"
-          }
+          "ok": false
         }
       }
     },
-    "9a3f65995021": {
+    "84f6bcad6466": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -338,7 +215,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -358,45 +236,20 @@
         }
       }
     },
-    "a92af671fd39": {
-      "name": "nativeChat.readSession#1",
-      "ordinal": 2,
-      "args": [
-        {
-          "name": "method",
-          "value": "nativeChat.readSession"
-        },
-        {
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-          "value": {
-            "agent": "claude",
-            "beforeOffset": 1200,
-            "limit": 60,
-            "sessionId": "session-1",
-            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
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-        "value": {
-          "id": "frame-2",
-          "ok": true,
-          "result": {
-            "$rpc": "null"
-          }
-        }
-      }
+    "8f91342d7840": {
+      "crash": {
+        "$rpc": "null"
+      },
+      "error": {
+        "$rpc": "null"
+      },
+      "hasMore": false,
+      "loadingEarlier": false,
+      "messageIds": ["m-1", "m-2", "m-3", "m-4", "m-5"],
+      "status": "ready",
+      "transcriptLoading": false
     },
-    "cea1d50a73fa": {
+    "911b3f485409": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -417,85 +270,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
-          }
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-        "settledAt": 0,
-        "value": {
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-            "message": "Unknown method"
-          },
-          "id": "frame-2",
-          "ok": false
-        }
-      }
-    },
-    "d163a9801643": {
-      "name": "nativeChat.readSession#1",
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-      "args": [
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-          "value": "nativeChat.readSession"
-        },
-        {
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-          "value": {
-            "agent": "claude",
-            "beforeOffset": 1200,
-            "limit": 60,
-            "sessionId": "session-1",
-            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
-          }
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-      }
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-    "d83fbb18104a": {
-      "name": "nativeChat.readSession#1",
-      "ordinal": 2,
-      "args": [
-        {
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-          "value": "nativeChat.readSession"
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-            "agent": "claude",
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-            "limit": 60,
-            "sessionId": "session-1",
-            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
-          }
-        },
-        {
-          "name": "options",
-          "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -539,7 +315,7 @@
         }
       }
     },
-    "dadae0a56731": {
+    "a3e69f56e5e2": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -560,7 +336,86 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
+          }
+        }
+      ],
+      "settlement": {
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+        "startedAt": 0,
+        "settledAt": 0,
+        "value": {
+          "id": "frame-2",
+          "ok": true,
+          "result": {
+            "$rpc": "null"
+          }
+        }
+      }
+    },
+    "ab5d827d2b71": {
+      "name": "nativeChat.readSession#1",
+      "ordinal": 2,
+      "args": [
+        {
+          "name": "method",
+          "value": "nativeChat.readSession"
+        },
+        {
+          "name": "params",
+          "value": {
+            "agent": "claude",
+            "beforeOffset": 1200,
+            "limit": 60,
+            "sessionId": "session-1",
+            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
+          }
+        },
+        {
+          "name": "options",
+          "value": {
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
+          }
+        }
+      ],
+      "settlement": {
+        "status": "fulfilled",
+        "startedAt": 0,
+        "settledAt": 0,
+        "value": {
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+          "ok": true,
+          "result": {
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+          }
+        }
+      }
+    },
+    "e88c218171fa": {
+      "name": "nativeChat.readSession#1",
+      "ordinal": 2,
+      "args": [
+        {
+          "name": "method",
+          "value": "nativeChat.readSession"
+        },
+        {
+          "name": "params",
+          "value": {
+            "agent": "claude",
+            "beforeOffset": 1200,
+            "limit": 60,
+            "sessionId": "session-1",
+            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
+          }
+        },
+        {
+          "name": "options",
+          "value": {
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -577,6 +432,46 @@
         "$rpc": "undefined"
       }
     },
+    "ee33a7e2ed08": {
+      "name": "nativeChat.readSession#1",
+      "ordinal": 2,
+      "args": [
+        {
+          "name": "method",
+          "value": "nativeChat.readSession"
+        },
+        {
+          "name": "params",
+          "value": {
+            "agent": "claude",
+            "beforeOffset": 1200,
+            "limit": 60,
+            "sessionId": "session-1",
+            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
+          }
+        },
+        {
+          "name": "options",
+          "value": {
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
+          }
+        }
+      ],
+      "settlement": {
+        "status": "fulfilled",
+        "startedAt": 0,
+        "settledAt": 0,
+        "value": {
+          "error": {
+            "code": "refused",
+            "message": ""
+          },
+          "id": "frame-2",
+          "ok": false
+        }
+      }
+    },
     "ee46c03cf1b8": {
       "crash": {
         "$rpc": "null"
@@ -589,6 +484,123 @@
       "messageIds": [],
       "status": "loading",
       "transcriptLoading": true
+    },
+    "fa953f37a758": {
+      "name": "nativeChat.readSession#1",
+      "ordinal": 2,
+      "args": [
+        {
+          "name": "method",
+          "value": "nativeChat.readSession"
+        },
+        {
+          "name": "params",
+          "value": {
+            "agent": "claude",
+            "beforeOffset": 1200,
+            "limit": 60,
+            "sessionId": "session-1",
+            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
+          }
+        },
+        {
+          "name": "options",
+          "value": {
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
+          }
+        }
+      ],
+      "settlement": {
+        "status": "fulfilled",
+        "startedAt": 0,
+        "settledAt": 0,
+        "value": {
+          "id": "frame-2",
+          "ok": true,
+          "result": {
+            "error": "inner refused",
+            "ok": false
+          }
+        }
+      }
+    },
+    "fcea12946cf7": {
+      "name": "nativeChat.readSession#1",
+      "ordinal": 2,
+      "args": [
+        {
+          "name": "method",
+          "value": "nativeChat.readSession"
+        },
+        {
+          "name": "params",
+          "value": {
+            "agent": "claude",
+            "beforeOffset": 1200,
+            "limit": 60,
+            "sessionId": "session-1",
+            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
+          }
+        },
+        {
+          "name": "options",
+          "value": {
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
+          }
+        }
+      ],
+      "settlement": {
+        "status": "fulfilled",
+        "startedAt": 0,
+        "settledAt": 0,
+        "value": {
+          "error": {
+            "code": "method_not_found",
+            "message": "Unknown method"
+          },
+          "id": "frame-2",
+          "ok": false
+        }
+      }
+    },
+    "fd440192b538": {
+      "name": "nativeChat.readSession#1",
+      "ordinal": 2,
+      "args": [
+        {
+          "name": "method",
+          "value": "nativeChat.readSession"
+        },
+        {
+          "name": "params",
+          "value": {
+            "agent": "claude",
+            "beforeOffset": 1200,
+            "limit": 60,
+            "sessionId": "session-1",
+            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
+          }
+        },
+        {
+          "name": "options",
+          "value": {
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
+          }
+        }
+      ],
+      "settlement": {
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+        "startedAt": 0,
+        "settledAt": 0,
+        "error": {
+          "category": "Error",
+          "message": "transport failure",
+          "isRpcDeliveryUnknown": true
+        }
+      }
     }
   },
   "recording": {
@@ -621,7 +633,7 @@
       {
         "id": "native-chat-page-earlier.prelude:paging",
         "observation": {
-          "sender": ["dadae0a56731"],
+          "sender": ["e88c218171fa"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -634,7 +646,7 @@
       {
         "id": "native-chat-page-earlier.normal:paged",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -647,7 +659,7 @@
       {
         "id": "native-chat-page-earlier.normal:re-subscribed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -661,7 +673,7 @@
       {
         "id": "native-chat-page-earlier.normal:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -675,7 +687,7 @@
       {
         "id": "native-chat-page-earlier.normal:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -696,7 +708,7 @@
       {
         "id": "native-chat-page-earlier.result-absent:paged",
         "observation": {
-          "sender": ["1821d5c2646a"],
+          "sender": ["75842f212e52"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -709,7 +721,7 @@
       {
         "id": "native-chat-page-earlier.result-absent:re-subscribed",
         "observation": {
-          "sender": ["1821d5c2646a"],
+          "sender": ["75842f212e52"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -723,7 +735,7 @@
       {
         "id": "native-chat-page-earlier.result-absent:replayed",
         "observation": {
-          "sender": ["1821d5c2646a"],
+          "sender": ["75842f212e52"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -737,7 +749,7 @@
       {
         "id": "native-chat-page-earlier.result-absent:unmounted",
         "observation": {
-          "sender": ["1821d5c2646a"],
+          "sender": ["75842f212e52"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -758,7 +770,7 @@
       {
         "id": "native-chat-page-earlier.result-null:paged",
         "observation": {
-          "sender": ["a92af671fd39"],
+          "sender": ["a3e69f56e5e2"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -771,7 +783,7 @@
       {
         "id": "native-chat-page-earlier.result-null:re-subscribed",
         "observation": {
-          "sender": ["a92af671fd39"],
+          "sender": ["a3e69f56e5e2"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -785,7 +797,7 @@
       {
         "id": "native-chat-page-earlier.result-null:replayed",
         "observation": {
-          "sender": ["a92af671fd39"],
+          "sender": ["a3e69f56e5e2"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -799,7 +811,7 @@
       {
         "id": "native-chat-page-earlier.result-null:unmounted",
         "observation": {
-          "sender": ["a92af671fd39"],
+          "sender": ["a3e69f56e5e2"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -820,7 +832,7 @@
       {
         "id": "native-chat-page-earlier.inner-ok-missing:paged",
         "observation": {
-          "sender": ["9a114b6ce2df"],
+          "sender": ["ab5d827d2b71"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -833,7 +845,7 @@
       {
         "id": "native-chat-page-earlier.inner-ok-missing:re-subscribed",
         "observation": {
-          "sender": ["9a114b6ce2df"],
+          "sender": ["ab5d827d2b71"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -847,7 +859,7 @@
       {
         "id": "native-chat-page-earlier.inner-ok-missing:replayed",
         "observation": {
-          "sender": ["9a114b6ce2df"],
+          "sender": ["ab5d827d2b71"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -861,7 +873,7 @@
       {
         "id": "native-chat-page-earlier.inner-ok-missing:unmounted",
         "observation": {
-          "sender": ["9a114b6ce2df"],
+          "sender": ["ab5d827d2b71"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -882,7 +894,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-string-error:paged",
         "observation": {
-          "sender": ["d163a9801643"],
+          "sender": ["fa953f37a758"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -895,7 +907,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-string-error:re-subscribed",
         "observation": {
-          "sender": ["d163a9801643"],
+          "sender": ["fa953f37a758"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -909,7 +921,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-string-error:replayed",
         "observation": {
-          "sender": ["d163a9801643"],
+          "sender": ["fa953f37a758"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -923,7 +935,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-string-error:unmounted",
         "observation": {
-          "sender": ["d163a9801643"],
+          "sender": ["fa953f37a758"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -944,7 +956,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-object-error:paged",
         "observation": {
-          "sender": ["9a3f65995021"],
+          "sender": ["84f6bcad6466"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -957,7 +969,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-object-error:re-subscribed",
         "observation": {
-          "sender": ["9a3f65995021"],
+          "sender": ["84f6bcad6466"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -971,7 +983,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-object-error:replayed",
         "observation": {
-          "sender": ["9a3f65995021"],
+          "sender": ["84f6bcad6466"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -985,7 +997,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-object-error:unmounted",
         "observation": {
-          "sender": ["9a3f65995021"],
+          "sender": ["84f6bcad6466"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -1006,7 +1018,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused:paged",
         "observation": {
-          "sender": ["41f222acdcb2"],
+          "sender": ["81eaceac1130"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1019,7 +1031,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused:re-subscribed",
         "observation": {
-          "sender": ["41f222acdcb2"],
+          "sender": ["81eaceac1130"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1033,7 +1045,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused:replayed",
         "observation": {
-          "sender": ["41f222acdcb2"],
+          "sender": ["81eaceac1130"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1047,7 +1059,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused:unmounted",
         "observation": {
-          "sender": ["41f222acdcb2"],
+          "sender": ["81eaceac1130"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -1068,7 +1080,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused-no-message:paged",
         "observation": {
-          "sender": ["2dd353a0e048"],
+          "sender": ["ee33a7e2ed08"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1081,7 +1093,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused-no-message:re-subscribed",
         "observation": {
-          "sender": ["2dd353a0e048"],
+          "sender": ["ee33a7e2ed08"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1095,7 +1107,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused-no-message:replayed",
         "observation": {
-          "sender": ["2dd353a0e048"],
+          "sender": ["ee33a7e2ed08"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1109,7 +1121,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused-no-message:unmounted",
         "observation": {
-          "sender": ["2dd353a0e048"],
+          "sender": ["ee33a7e2ed08"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -1130,7 +1142,7 @@
       {
         "id": "native-chat-page-earlier.method-not-found:paged",
         "observation": {
-          "sender": ["cea1d50a73fa"],
+          "sender": ["fcea12946cf7"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1143,7 +1155,7 @@
       {
         "id": "native-chat-page-earlier.method-not-found:re-subscribed",
         "observation": {
-          "sender": ["cea1d50a73fa"],
+          "sender": ["fcea12946cf7"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1157,7 +1169,7 @@
       {
         "id": "native-chat-page-earlier.method-not-found:replayed",
         "observation": {
-          "sender": ["cea1d50a73fa"],
+          "sender": ["fcea12946cf7"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1171,7 +1183,7 @@
       {
         "id": "native-chat-page-earlier.method-not-found:unmounted",
         "observation": {
-          "sender": ["cea1d50a73fa"],
+          "sender": ["fcea12946cf7"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -1192,7 +1204,7 @@
       {
         "id": "native-chat-page-earlier.transport-rejection:paged",
         "observation": {
-          "sender": ["63d9cc126261"],
+          "sender": ["fd440192b538"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1205,7 +1217,7 @@
       {
         "id": "native-chat-page-earlier.transport-rejection:re-subscribed",
         "observation": {
-          "sender": ["63d9cc126261"],
+          "sender": ["fd440192b538"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1219,7 +1231,7 @@
       {
         "id": "native-chat-page-earlier.transport-rejection:replayed",
         "observation": {
-          "sender": ["63d9cc126261"],
+          "sender": ["fd440192b538"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1233,7 +1245,7 @@
       {
         "id": "native-chat-page-earlier.transport-rejection:unmounted",
         "observation": {
-          "sender": ["63d9cc126261"],
+          "sender": ["fd440192b538"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -1254,7 +1266,7 @@
       {
         "id": "native-chat-page-earlier.transport-rejection-no-message:paged",
         "observation": {
-          "sender": ["7ee0fd6f2bd8"],
+          "sender": ["65ff352ca953"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1267,7 +1279,7 @@
       {
         "id": "native-chat-page-earlier.transport-rejection-no-message:re-subscribed",
         "observation": {
-          "sender": ["7ee0fd6f2bd8"],
+          "sender": ["65ff352ca953"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1281,7 +1293,7 @@
       {
         "id": "native-chat-page-earlier.transport-rejection-no-message:replayed",
         "observation": {
-          "sender": ["7ee0fd6f2bd8"],
+          "sender": ["65ff352ca953"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -1295,7 +1307,7 @@
       {
         "id": "native-chat-page-earlier.transport-rejection-no-message:unmounted",
         "observation": {
-          "sender": ["7ee0fd6f2bd8"],
+          "sender": ["65ff352ca953"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
diff --git a/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.subscribe-1-1.json b/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.subscribe-1-1.json
index 430461becfc..859409c0e68 100644
--- a/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.subscribe-1-1.json
+++ b/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.subscribe-1-1.json
@@ -115,6 +115,72 @@
       "status": "ready",
       "transcriptLoading": false
     },
+    "911b3f485409": {
+      "name": "nativeChat.readSession#1",
+      "ordinal": 2,
+      "args": [
+        {
+          "name": "method",
+          "value": "nativeChat.readSession"
+        },
+        {
+          "name": "params",
+          "value": {
+            "agent": "claude",
+            "beforeOffset": 1200,
+            "limit": 60,
+            "sessionId": "session-1",
+            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
+          }
+        },
+        {
+          "name": "options",
+          "value": {
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
+          }
+        }
+      ],
+      "settlement": {
+        "status": "fulfilled",
+        "startedAt": 0,
+        "settledAt": 0,
+        "value": {
+          "id": "frame-2",
+          "ok": true,
+          "result": {
+            "beforeOffset": 0,
+            "hasMore": false,
+            "messages": [
+              {
+                "blocks": [
+                  {
+                    "text": "first",
+                    "type": "text"
+                  }
+                ],
+                "id": "m-1",
+                "role": "assistant",
+                "source": "transcript",
+                "timestamp": 1000
+              },
+              {
+                "blocks": [
+                  {
+                    "text": "second",
+                    "type": "text"
+                  }
+                ],
+                "id": "m-2",
+                "role": "assistant",
+                "source": "transcript",
+                "timestamp": 2000
+              }
+            ]
+          }
+        }
+      }
+    },
     "96abfc4cef7e": {
       "name": "nativeChat.unsubscribe#1",
       "ordinal": 4,
@@ -185,7 +251,7 @@
       "status": "error",
       "transcriptLoading": false
     },
-    "d83fbb18104a": {
+    "e88c218171fa": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -206,72 +272,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
-          }
-        }
-      ],
-      "settlement": {
-        "status": "fulfilled",
-        "startedAt": 0,
-        "settledAt": 0,
-        "value": {
-          "id": "frame-2",
-          "ok": true,
-          "result": {
-            "beforeOffset": 0,
-            "hasMore": false,
-            "messages": [
-              {
-                "blocks": [
-                  {
-                    "text": "first",
-                    "type": "text"
-                  }
-                ],
-                "id": "m-1",
-                "role": "assistant",
-                "source": "transcript",
-                "timestamp": 1000
-              },
-              {
-                "blocks": [
-                  {
-                    "text": "second",
-                    "type": "text"
-                  }
-                ],
-                "id": "m-2",
-                "role": "assistant",
-                "source": "transcript",
-                "timestamp": 2000
-              }
-            ]
-          }
-        }
-      }
-    },
-    "dadae0a56731": {
-      "name": "nativeChat.readSession#1",
-      "ordinal": 2,
-      "args": [
-        {
-          "name": "method",
-          "value": "nativeChat.readSession"
-        },
-        {
-          "name": "params",
-          "value": {
-            "agent": "claude",
-            "beforeOffset": 1200,
-            "limit": 60,
-            "sessionId": "session-1",
-            "transcriptPath": "/work/feature/.claude/session-1.jsonl"
-          }
-        },
-        {
-          "name": "options",
-          "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -361,7 +363,7 @@
       {
         "id": "native-chat-page-earlier.normal:paging",
         "observation": {
-          "sender": ["dadae0a56731"],
+          "sender": ["e88c218171fa"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -374,7 +376,7 @@
       {
         "id": "native-chat-page-earlier.normal:paged",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -387,7 +389,7 @@
       {
         "id": "native-chat-page-earlier.normal:re-subscribed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -401,7 +403,7 @@
       {
         "id": "native-chat-page-earlier.normal:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -415,7 +417,7 @@
       {
         "id": "native-chat-page-earlier.normal:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
diff --git a/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.subscribe-2-1.json b/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.subscribe-2-1.json
index 516ef620bf7..06f5faea844 100644
--- a/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.subscribe-2-1.json
+++ b/mobile/rpc-foundation/goldens/matrix-session.native-chat-page-nativechat.subscribe-2-1.json
@@ -105,40 +105,7 @@
       "status": "ready",
       "transcriptLoading": false
     },
-    "a5609c6d15fc": {
-      "crash": {
-        "$rpc": "null"
-      },
-      "error": "Unknown method",
-      "hasMore": false,
-      "loadingEarlier": false,
-      "messageIds": ["m-1", "m-2", "m-3", "m-4"],
-      "status": "error",
-      "transcriptLoading": false
-    },
-    "b96b63e4aaf3": {
-      "crash": {
-        "$rpc": "null"
-      },
-      "error": "outer refused",
-      "hasMore": false,
-      "loadingEarlier": false,
-      "messageIds": ["m-1", "m-2", "m-3", "m-4"],
-      "status": "error",
-      "transcriptLoading": false
-    },
-    "d53372f95573": {
-      "crash": {
-        "$rpc": "null"
-      },
-      "error": "",
-      "hasMore": false,
-      "loadingEarlier": false,
-      "messageIds": ["m-1", "m-2", "m-3", "m-4"],
-      "status": "error",
-      "transcriptLoading": false
-    },
-    "d83fbb18104a": {
+    "911b3f485409": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -159,7 +126,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -203,7 +171,45 @@
         }
       }
     },
-    "dadae0a56731": {
+    "a5609c6d15fc": {
+      "crash": {
+        "$rpc": "null"
+      },
+      "error": "Unknown method",
+      "hasMore": false,
+      "loadingEarlier": false,
+      "messageIds": ["m-1", "m-2", "m-3", "m-4"],
+      "status": "error",
+      "transcriptLoading": false
+    },
+    "b96b63e4aaf3": {
+      "crash": {
+        "$rpc": "null"
+      },
+      "error": "outer refused",
+      "hasMore": false,
+      "loadingEarlier": false,
+      "messageIds": ["m-1", "m-2", "m-3", "m-4"],
+      "status": "error",
+      "transcriptLoading": false
+    },
+    "d53372f95573": {
+      "crash": {
+        "$rpc": "null"
+      },
+      "error": "",
+      "hasMore": false,
+      "loadingEarlier": false,
+      "messageIds": ["m-1", "m-2", "m-3", "m-4"],
+      "status": "error",
+      "transcriptLoading": false
+    },
+    "e4483b4ab66e": {
+      "name": "nativeChat.unsubscribe#2",
+      "ordinal": 7,
+      "json": "{\"id\":\"frame-5\",\"deviceToken\":\"recording-device\",\"method\":\"nativeChat.unsubscribe\",\"params\":{\"subscriptionId\":\"claude:session-1:00000000-0000-4000-8000-000000000001\"}}"
+    },
+    "e88c218171fa": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -224,7 +230,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -233,11 +240,6 @@
         "startedAt": 0
       }
     },
-    "e4483b4ab66e": {
-      "name": "nativeChat.unsubscribe#2",
-      "ordinal": 7,
-      "json": "{\"id\":\"frame-5\",\"deviceToken\":\"recording-device\",\"method\":\"nativeChat.unsubscribe\",\"params\":{\"subscriptionId\":\"claude:session-1:00000000-0000-4000-8000-000000000001\"}}"
-    },
     "eb79a9b3682a": {
       "status": "fulfilled",
       "startedAt": 0,
@@ -290,7 +292,7 @@
       {
         "id": "native-chat-page-earlier.prelude:paging",
         "observation": {
-          "sender": ["dadae0a56731"],
+          "sender": ["e88c218171fa"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -303,7 +305,7 @@
       {
         "id": "native-chat-page-earlier.prelude:paged",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -316,7 +318,7 @@
       {
         "id": "native-chat-page-earlier.prelude:re-subscribed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -330,7 +332,7 @@
       {
         "id": "native-chat-page-earlier.normal:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -344,7 +346,7 @@
       {
         "id": "native-chat-page-earlier.normal:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -365,7 +367,7 @@
       {
         "id": "native-chat-page-earlier.result-absent:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -379,7 +381,7 @@
       {
         "id": "native-chat-page-earlier.result-absent:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -400,7 +402,7 @@
       {
         "id": "native-chat-page-earlier.result-null:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -414,7 +416,7 @@
       {
         "id": "native-chat-page-earlier.result-null:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -435,7 +437,7 @@
       {
         "id": "native-chat-page-earlier.inner-ok-missing:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -449,7 +451,7 @@
       {
         "id": "native-chat-page-earlier.inner-ok-missing:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -470,7 +472,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-string-error:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -484,7 +486,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-string-error:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -505,7 +507,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-object-error:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -519,7 +521,7 @@
       {
         "id": "native-chat-page-earlier.inner-false-object-error:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
@@ -540,7 +542,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -554,7 +556,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -569,7 +571,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused-no-message:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -583,7 +585,7 @@
       {
         "id": "native-chat-page-earlier.outer-refused-no-message:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -598,7 +600,7 @@
       {
         "id": "native-chat-page-earlier.method-not-found:replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -612,7 +614,7 @@
       {
         "id": "native-chat-page-earlier.method-not-found:unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
diff --git a/mobile/rpc-foundation/goldens/native-chat-page-earlier.json b/mobile/rpc-foundation/goldens/native-chat-page-earlier.json
index e77f69f1b73..a2e8ea89078 100644
--- a/mobile/rpc-foundation/goldens/native-chat-page-earlier.json
+++ b/mobile/rpc-foundation/goldens/native-chat-page-earlier.json
@@ -81,7 +81,7 @@
       "status": "ready",
       "transcriptLoading": false
     },
-    "d83fbb18104a": {
+    "911b3f485409": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -102,7 +102,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -146,7 +147,7 @@
         }
       }
     },
-    "dadae0a56731": {
+    "e88c218171fa": {
       "name": "nativeChat.readSession#1",
       "ordinal": 2,
       "args": [
@@ -167,7 +168,8 @@
         {
           "name": "options",
           "value": {
-            "$rpc": "absent"
+            "budgetSpansConnect": true,
+            "timeoutMs": 15000
           }
         }
       ],
@@ -228,7 +230,7 @@
       {
         "id": "paging",
         "observation": {
-          "sender": ["dadae0a56731"],
+          "sender": ["e88c218171fa"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -241,7 +243,7 @@
       {
         "id": "paged",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -254,7 +256,7 @@
       {
         "id": "re-subscribed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -268,7 +270,7 @@
       {
         "id": "replayed",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": ["456781b97acc", "08ef53d83e8c", "663babae1f1d", "7eedfcf76fd3"],
           "settlements": {
             "mount": "eb79a9b3682a",
@@ -282,7 +284,7 @@
       {
         "id": "unmounted",
         "observation": {
-          "sender": ["d83fbb18104a"],
+          "sender": ["911b3f485409"],
           "payloads": [
             "456781b97acc",
             "08ef53d83e8c",
diff --git a/mobile/src/session/MobileNativeChatDiffCard.tsx b/mobile/src/session/MobileNativeChatDiffCard.tsx
index 080e32fe24a..e7e6eae9cdf 100644
--- a/mobile/src/session/MobileNativeChatDiffCard.tsx
+++ b/mobile/src/session/MobileNativeChatDiffCard.tsx
@@ -1,5 +1,6 @@
 import { useMemo } from 'react'
-import { Pressable, ScrollView, Text, View } from 'react-native'
+import { Pressable, Text, View } from 'react-native'
+import { MobileNativeChatOwnedScrollView } from './MobileNativeChatOwnedScrollView'
 import { ChevronRight, FileMinus2, FilePen, FilePlus2 } from 'lucide-react-native'
 import {
   NATIVE_CHAT_DIFF_CARD_COPY,
@@ -83,7 +84,17 @@ function DiffRow({
 
 /** The card's rows in their own bounded box. Its own component so a collapsed card
  *  builds none of them. */
-function DiffCardRows({ file, fontScale }: { file: NativeChatEditFile; fontScale: number }) {
+function DiffCardRows({
+  file,
+  fontScale,
+  disclosureKey,
+  rootIdentity
+}: {
+  file: NativeChatEditFile
+  fontScale: number
+  disclosureKey?: string
+  rootIdentity?: string
+}) {
   const onLayout = useMobileNativeChatOpenedDetail()
   const type = toolType(fontScale).code
   // A snippet-relative number would read as a file position, so the gutter is blank
@@ -95,7 +106,9 @@ function DiffCardRows({ file, fontScale }: { file: NativeChatEditFile; fontScale
   // Desktop's row identity: the line itself, and which repeat of it this is.
   const seen = new Map<string, number>()
   return (
-    <ScrollView
+    <MobileNativeChatOwnedScrollView
+      rootIdentity={rootIdentity ?? `diff:${file.path}`}
+      positionKey={disclosureKey ?? `diff:${file.path}`}
       style={[styles.codeBox, styles.diffBody]}
       nestedScrollEnabled
       keyboardShouldPersistTaps="handled"
@@ -114,7 +127,7 @@ function DiffCardRows({ file, fontScale }: { file: NativeChatEditFile; fontScale
           />
         )
       })}
-    </ScrollView>
+    </MobileNativeChatOwnedScrollView>
   )
 }
 
@@ -125,6 +138,7 @@ export function MobileNativeChatDiffCard({
   fontScale,
   defaultExpanded = false,
   disclosureKey,
+  rootIdentity,
   onOpenFile
 }: {
   file: NativeChatEditFile
@@ -132,6 +146,7 @@ export function MobileNativeChatDiffCard({
   defaultExpanded?: boolean
   /** Identity this card's open state is remembered under while it is unmounted. */
   disclosureKey?: string
+  rootIdentity?: string
   onOpenFile?: (path: string) => void
 }): React.JSX.Element {
   const [expanded, setExpanded] = useMobileNativeChatDisclosure(disclosureKey, defaultExpanded)
@@ -201,7 +216,14 @@ export function MobileNativeChatDiffCard({
           accessibilityLabel={NATIVE_CHAT_DIFF_CARD_COPY.copyDiff}
         />
       </View>
-      {hasBody && expanded ? <DiffCardRows file={file} fontScale={fontScale} /> : null}
+      {hasBody && expanded ? (
+        <DiffCardRows
+          file={file}
+          fontScale={fontScale}
+          disclosureKey={disclosureKey}
+          rootIdentity={rootIdentity}
+        />
+      ) : null}
     </View>
   )
 }
diff --git a/mobile/src/session/MobileNativeChatLiveLine.tsx b/mobile/src/session/MobileNativeChatLiveLine.tsx
index b38c65697f8..c753111a15d 100644
--- a/mobile/src/session/MobileNativeChatLiveLine.tsx
+++ b/mobile/src/session/MobileNativeChatLiveLine.tsx
@@ -64,6 +64,7 @@ export function MobileNativeChatLiveLine({
       {reasoning && open ? (
         <View style={styles.body}>
           <MobileNativeChatReasoningBody
+            positionKey={nativeChatReasoningDisclosureKey(reasoning.message.id)}
             markdown={reasoning.markdown}
             fontScale={fontScale}
             onOpenFile={onOpenFile}
diff --git a/mobile/src/session/MobileNativeChatMessage.tool-result-availability.test.tsx b/mobile/src/session/MobileNativeChatMessage.tool-result-availability.test.tsx
index 0729b2200d6..73813e6abc9 100644
--- a/mobile/src/session/MobileNativeChatMessage.tool-result-availability.test.tsx
+++ b/mobile/src/session/MobileNativeChatMessage.tool-result-availability.test.tsx
@@ -68,6 +68,10 @@ vi.mock('./MobileNativeChatMessageActionsSheet', () => ({
 }))
 
 import { MobileNativeChatMessage } from './MobileNativeChatMessage'
+import {
+  MobileNativeChatDisclosureContext,
+  useMobileNativeChatDisclosures
+} from './mobile-native-chat-disclosure-store'
 
 function message(blocks: NativeChatMessage['blocks']): NativeChatMessage {
   return { id: 'source', role: 'assistant', blocks, timestamp: 1, source: 'transcript' }
@@ -127,6 +131,64 @@ describe('mobile tool result availability', () => {
     return renderer!
   }
 
+  // The page's window unmounts a row scrolled past; older messages joining its fold change its id.
+  it('keeps what the reader opened in a windowed-out row by its row key, per Tools default', () => {
+    const row = message([
+      { type: 'tool-call', callId: 'one', name: 'Bash', input: 'first input' },
+      { type: 'tool-result', callId: 'one', output: 'first output' },
+      { type: 'tool-call', callId: 'two', name: 'Bash', input: 'second input' },
+      { type: 'tool-result', callId: 'two', output: 'second output' }
+    ])
+    function Window({ shown, id, tools }: { shown: boolean; id: string; tools: boolean }) {
+      const disclosures = useMobileNativeChatDisclosures('chat')
+      return createElement(
+        MobileNativeChatDisclosureContext.Provider,
+        { value: disclosures },
+        shown
+          ? createElement(MobileNativeChatMessage, {
+              message: { ...row, id },
+              rowKey: 'kept',
+              toolsExpanded: tools
+            })
+          : null
+      )
+    }
+    const draw = (shown: boolean, id = 'source', tools = false) =>
+      act(() => {
+        const element = createElement(Window, { shown, id, tools })
+        if (renderer) {
+          renderer.update(element)
+        } else {
+          renderer = create(element)
+        }
+      })
+    const header = () =>
+      renderer!.root.find(
+        (node) =>
+          String(node.type) === 'Pressable' && node.props.accessibilityLiveRegion === 'polite'
+      )
+    draw(true)
+    press(header())
+    press(button(renderer!.root, 'first input'))
+    draw(false)
+    draw(true, 'older-head')
+    expect(toolLines(renderer!.root)).toHaveLength(2)
+    expect(textIn(renderer!.root)).toContain('first output')
+    expect(textIn(renderer!.root)).not.toContain('second output')
+
+    // Tools opens every run and line; the reader closes this run under that default.
+    draw(true, 'older-head', true)
+    expect(textIn(renderer!.root)).toContain('second output')
+    press(header())
+    draw(false, 'older-head', true)
+    draw(true, 'older-head', true)
+    expect(toolLines(renderer!.root)).toHaveLength(0)
+    // Back to the old default: the choices made under it come back.
+    draw(true, 'older-head', false)
+    expect(textIn(renderer!.root)).toContain('first output')
+    expect(textIn(renderer!.root)).not.toContain('second output')
+  })
+
   it('draws each orphan output as its own Result row under one Result header', () => {
     const raw = message(
       Array.from({ length: 8 }, (_, index) => ({
diff --git a/mobile/src/session/MobileNativeChatMessage.tsx b/mobile/src/session/MobileNativeChatMessage.tsx
index 02f74d11afc..cea4d2baf74 100644
--- a/mobile/src/session/MobileNativeChatMessage.tsx
+++ b/mobile/src/session/MobileNativeChatMessage.tsx
@@ -22,6 +22,7 @@ import { MobileSourceCopyButton } from '../components/MobileSourceCopyButton'
 import { nativeChatMessagePlainText } from './mobile-native-chat-message-plain-text'
 import { deriveNativeChatRowContent } from '../../../src/shared/native-chat-row-content'
 import { MobileNativeChatReasoningRow } from './MobileNativeChatReasoningRow'
+import { mobileNativeChatRowId } from './MobileNativeChatScrollHold'
 import { nativeChatWorkRunEntries } from '../../../src/shared/native-chat-work-run'
 import { nativeChatReasoningDisclosureKey } from '../../../src/shared/native-chat-reasoning-row'
 import { MobileNativeChatTurnStatus } from './MobileNativeChatTurnStatus'
@@ -47,6 +48,8 @@ import { Prose } from './MobileNativeChatProse'
 
 function MobileNativeChatMessageImpl({
   message,
+  rowKey,
+  runOwner,
   mayStillGrow = false,
   toolsExpanded = false,
   previousTodoWrite,
@@ -77,6 +80,9 @@ function MobileNativeChatMessageImpl({
   onToggleUserMessage
 }: {
   message: NativeChatMessage
+  /** The row's place on the page, kept while older messages join it; tags the row. */
+  rowKey?: string
+  runOwner?: string
   /** The newest assistant row of a live turn with no prompt open: its last text may still grow. */
   mayStillGrow?: boolean
   toolsExpanded?: boolean
@@ -213,7 +219,7 @@ function MobileNativeChatMessageImpl({
     return (
       <>
         {turnStatusAbove ? statusRow : null}
-        <View style={styles.row}>
+        <View style={styles.row} testID={mobileNativeChatRowId(rowKey ?? message.id)}>
           <MobileNativeChatResolutionReceipt
             body={receipt}
             awaiting={awaiting}
@@ -234,7 +240,7 @@ function MobileNativeChatMessageImpl({
       <>
         {turnStatusAbove ? statusRow : null}
         {draws ? (
-          <View style={styles.row}>
+          <View style={styles.row} testID={mobileNativeChatRowId(rowKey ?? message.id)}>
             <MobileNativeChatReasoningRow
               message={message}
               markdown={markdown}
@@ -281,7 +287,10 @@ function MobileNativeChatMessageImpl({
     <>
       {/* A turn with no user bubble carries its bar above its first row. */}
       {turnStatusAbove ? statusRow : null}
-      <View style={[styles.row, isUser && styles.rowUser]}>
+      <View
+        style={[styles.row, isUser && styles.rowUser]}
+        testID={mobileNativeChatRowId(rowKey ?? message.id)}
+      >
         <Content
           onLongPress={onLongPress}
           style={[
@@ -335,7 +344,7 @@ function MobileNativeChatMessageImpl({
               // default every run and line reads, and a reader's own choice is kept per default.
               defaultExpanded={toolsExpanded}
               expandChildren={toolsExpanded}
-              disclosureId={message.id}
+              disclosureId={runOwner ?? rowKey ?? message.id}
               asides={asides}
               activeTurnIsWorking={structuredActivityUi ? activeTurnIsWorking : undefined}
               trailing={trailingRun}
diff --git a/mobile/src/session/MobileNativeChatOverlay.tsx b/mobile/src/session/MobileNativeChatOverlay.tsx
index 23a09de9343..ca39a56db28 100644
--- a/mobile/src/session/MobileNativeChatOverlay.tsx
+++ b/mobile/src/session/MobileNativeChatOverlay.tsx
@@ -2,6 +2,7 @@ import { useMemo } from 'react'
 import { StyleSheet, View } from 'react-native'
 import { MobileNativeChatView, type MobileNativeChatInputLockReason } from './MobileNativeChatView'
 import { foldMobileNativeChatMessages } from './mobile-native-chat-render-data'
+import { useMobileNativeChatFoldReuse } from './mobile-native-chat-fold-reuse'
 import type { MobileNativeChatImageAttachments } from './use-mobile-native-chat-image-attachments'
 import type { MobileNativeChatController } from './use-mobile-native-chat-controller'
 import type { MobileNativeChatStructuredComposer } from './MobileNativeChatComposer'
@@ -69,9 +70,9 @@ export function MobileNativeChatOverlay({
   const session = controller.nativeChatSession
   // The chat is drawn only with a resolved agent; the fallback never reaches the screen.
   const agent = controller.nativeChatAgent ?? ''
-  const folded = useMemo(
-    () => foldMobileNativeChatMessages(session.messages, agent),
-    [session.messages, agent]
+  const folded = useMobileNativeChatFoldReuse(
+    useMemo(() => foldMobileNativeChatMessages(session.messages, agent), [session.messages, agent]),
+    sendSurfaceId
   )
   const streaming = useMobileNativeChatStreamingBubble(
     folded,
@@ -142,7 +143,7 @@ export function MobileNativeChatOverlay({
               composerTray={composerTray}
               onOpenFile={onOpenFile}
               hasMore={session.hasMore}
-              loadingEarlier={session.loadingEarlier}
+              olderPages={session.olderPages}
               onLoadEarlier={session.loadEarlier}
               onSend={images.sendNativeChat}
               sendSurfaceId={sendSurfaceId}
diff --git a/mobile/src/session/MobileNativeChatOwnedScrollView.tsx b/mobile/src/session/MobileNativeChatOwnedScrollView.tsx
new file mode 100644
index 00000000000..3827843c67e
--- /dev/null
+++ b/mobile/src/session/MobileNativeChatOwnedScrollView.tsx
@@ -0,0 +1,88 @@
+import {
+  createContext,
+  useCallback,
+  useContext,
+  useLayoutEffect,
+  useMemo,
+  useRef,
+  type ComponentProps,
+  type Ref
+} from 'react'
+import { Platform, ScrollView } from 'react-native'
+import { MobileNativeChatDisclosureContext } from './mobile-native-chat-disclosure-store'
+
+const RootAddress = createContext<{ id: string; address: string; owner: string } | null>(null)
+
+/** Every vertical transcript viewport declares its owner, even before it overflows. */
+export function MobileNativeChatOwnedScrollView({
+  positionKey,
+  rootIdentity = positionKey,
+  owner,
+  initialFollow = false,
+  followKey,
+  ref,
+  children,
+  ...props
+}: ComponentProps<typeof ScrollView> & {
+  positionKey: string
+  rootIdentity?: string
+  owner?: string
+  initialFollow?: boolean
+  followKey?: number
+  ref?: Ref<ScrollView>
+}) {
+  const store = useContext(MobileNativeChatDisclosureContext)
+  const parent = useContext(RootAddress)
+  const id = parent ? `${parent.id}/${rootIdentity}` : rootIdentity
+  const address = parent ? `${parent.address}/${positionKey}` : positionKey
+  const rootOwner = owner ?? parent?.owner ?? id
+  const value = useMemo(() => ({ id, address, owner: rootOwner }), [id, address, rootOwner])
+  const roots = store?.roots
+  const scroll = useRef<ScrollView>(null)
+  const release = useRef<(() => void) | undefined>(undefined)
+  const attach = useCallback(
+    (node: ScrollView | null) => {
+      scroll.current = node
+      if (typeof ref === 'function') {
+        return ref(node)
+      }
+      if (ref) {
+        ref.current = node
+      }
+    },
+    [ref]
+  )
+  useLayoutEffect(
+    () => () => {
+      release.current?.()
+      release.current = undefined
+    },
+    [roots, id]
+  )
+  useLayoutEffect(() => {
+    if (Platform.OS !== 'web' || !roots) {
+      return
+    }
+    const node: unknown = scroll.current?.getScrollableNode()
+    if (
+      typeof HTMLElement !== 'undefined' &&
+      node instanceof HTMLElement &&
+      node.firstElementChild !== null
+    ) {
+      release.current = roots.register(
+        id,
+        node,
+        node.firstElementChild,
+        rootOwner,
+        address,
+        initialFollow
+      )
+      roots.layout(id, address, followKey)
+    }
+  })
+  return (
+    <ScrollView {...props} ref={attach}>
+      <RootAddress.Provider value={value}>{children}</RootAddress.Provider>
+    </ScrollView>
+  )
+}
diff --git a/mobile/src/session/MobileNativeChatPageList.tsx b/mobile/src/session/MobileNativeChatPageList.tsx
new file mode 100644
index 00000000000..8a0edc28e82
--- /dev/null
+++ b/mobile/src/session/MobileNativeChatPageList.tsx
@@ -0,0 +1,142 @@
+import {
+  Fragment,
+  useCallback,
+  useImperativeHandle,
+  useLayoutEffect,
+  useRef,
+  type ReactElement,
+  type Ref
+} from 'react'
+import {
+  View,
+  type NativeScrollEvent,
+  type NativeSyntheticEvent,
+  type ScrollView,
+  type StyleProp,
+  type ViewStyle
+} from 'react-native'
+import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
+import type { MobileNativeChatRowKeys } from './mobile-native-chat-row-keys'
+import { MobileNativeChatPageScroll, outOfAnchoring } from './MobileNativeChatPageScroll'
+import type { MobileNativeChatListHandle } from './use-mobile-native-chat-tail-follow'
+import type { MobileNativeChatTurnRow } from './use-mobile-native-chat-turn-disclosure'
+import type { MobileNativeChatWindowScroller } from './mobile-native-chat-page-window-state'
+import { useMobileNativeChatPageWindow } from './use-mobile-native-chat-page-window'
+import type { MobileNativeChatScrollRoots } from './mobile-native-chat-scroll-roots'
+
+type Row = { item: NativeChatMessage; index: number }
+
+type Props = {
+  roots?: MobileNativeChatScrollRoots
+  ref: Ref<MobileNativeChatListHandle>
+  endAnchored: boolean
+  isFollowing: () => boolean
+  pin: () => void
+  rows: readonly NativeChatMessage[]
+  rowKeys: Pick<MobileNativeChatRowKeys, 'scope' | 'sourceHead' | 'keyOf' | 'current'>
+  renderItem: (row: Row) => ReactElement
+  /** What a row draws besides itself; a height measured for other state no longer holds. */
+  rowState: (index: number, row: NativeChatMessage) => MobileNativeChatTurnRow
+  layoutKey: string
+  contentContainerStyle: StyleProp<ViewStyle>
+  /** `measuring`: rows above are not measured yet, so the Load earlier slot shows loading. */
+  header: (measuring: boolean) => ReactElement | null
+  footer: ReactElement | null
+  emptyStateView: ReactElement | null
+  onScroll: (event: NativeSyntheticEvent<NativeScrollEvent>) => void
+}
+
+/** The page's transcript in one keyed flow: RN Web's list draws by index after paint, so opens climbed
+ *  and older pages went in its header, where iOS stopped scrolling at the seam. */
+export function MobileNativeChatPageList({
+  ref,
+  roots,
+  endAnchored,
+  isFollowing,
+  pin,
+  rows,
+  rowKeys,
+  renderItem,
+  rowState,
+  layoutKey,
+  contentContainerStyle,
+  header,
+  footer,
+  emptyStateView,
+  onScroll
+}: Props): ReactElement {
+  const scroll = useRef<ScrollView>(null)
+  const scroller = useCallback(
+    (): MobileNativeChatWindowScroller | null | undefined => scroll.current?.getScrollableNode(),
+    []
+  )
+  const { view, rowRef, list } = useMobileNativeChatPageWindow({
+    roots,
+    rows,
+    rowKeys,
+    rowState,
+    following: endAnchored,
+    isFollowing,
+    layoutKey,
+    scroller
+  })
+  useImperativeHandle(
+    ref,
+    () => ({
+      getScrollableNode: () => scroll.current?.getScrollableNode(),
+      scrollToOffset: ({ offset, animated }) => {
+        list.wrote(offset)
+        scroll.current?.scrollTo({ y: offset, animated })
+      },
+      scrollToEnd: (params) => scroll.current?.scrollToEnd(params),
+      ...list
+    }),
+    [list]
+  )
+  // After the handle attaches, so a chat's first paint is at its end; later growth the observer pins.
+  const opened = useRef('')
+  const shown = `${rowKeys.scope}:${rows.length > 0}`
+  useLayoutEffect(() => {
+    if (opened.current !== shown) {
+      opened.current = shown
+      pin()
+    }
+  }, [shown, pin])
+
+  const drawRow = (item: NativeChatMessage, index: number) => {
+    const key = rowKeys.keyOf(item)
+    return (
+      <View key={key} ref={rowRef(key)}>
+        {renderItem({ item, index })}
+      </View>
+    )
+  }
+  return (
+    <MobileNativeChatPageScroll
+      ref={scroll}
+      contentContainerStyle={contentContainerStyle}
+      // Let link/file taps land while the composer keyboard is up
+      // instead of being swallowed by the dismiss gesture.
+      keyboardShouldPersistTaps="handled"
+      onScroll={onScroll}
+      scrollEventThrottle={32}
+    >
+      {/* Never what the browser's anchoring holds: rows land below it, and spacers stand in for rows. */}
+      <View style={outOfAnchoring}>{header(view.measuring)}</View>
+      {rows.length === 0 ? (
+        emptyStateView
+      ) : (
+        // Keyed by the chat, so no row carries into another. Rows unmount once scrolled past; what
+        // the reader opened in them is kept in the chat's disclosure store, above the list.
+        <Fragment key={rowKeys.scope}>
+          <View style={[outOfAnchoring, { height: view.above }]} />
+          {rows.slice(view.m0, view.m1).map((item, at) => drawRow(item, view.m0 + at))}
+          <View style={[outOfAnchoring, { height: view.mid }]} />
+          {rows.slice(view.start, view.end).map((item, at) => drawRow(item, view.start + at))}
+          <View style={[outOfAnchoring, { height: view.bottom }]} />
+        </Fragment>
+      )}
+      {footer}
+    </MobileNativeChatPageScroll>
+  )
+}
diff --git a/mobile/src/session/MobileNativeChatPageScroll.tsx b/mobile/src/session/MobileNativeChatPageScroll.tsx
new file mode 100644
index 00000000000..edc833f5786
--- /dev/null
+++ b/mobile/src/session/MobileNativeChatPageScroll.tsx
@@ -0,0 +1,28 @@
+import type { Ref } from 'react'
+import { ScrollView, StyleSheet, View, type ScrollViewProps, type ViewStyle } from 'react-native'
+
+/** The page's scroller. Where the browser has scroll anchoring it keeps a parked reader's place;
+ *  the page turns it off on the scroller itself while it owns the scroll (following, a place-hold). */
+export function MobileNativeChatPageScroll({
+  ref,
+  children,
+  contentContainerStyle,
+  ...props
+}: ScrollViewProps & { ref?: Ref<ScrollView> }) {
+  return (
+    <ScrollView ref={ref} {...props} contentContainerStyle={pageScroll.fill}>
+      <View style={contentContainerStyle}>{children}</View>
+    </ScrollView>
+  )
+}
+
+// RN Web passes it through to CSS; ViewStyle doesn't name it.
+const anchorless: ViewStyle & { overflowAnchor: 'none' } = { overflowAnchor: 'none' }
+
+const pageScroll = StyleSheet.create({
+  fill: { flexGrow: 1 },
+  anchorless
+})
+
+/** Never the node the browser's anchoring holds. */
+export const outOfAnchoring = pageScroll.anchorless
diff --git a/mobile/src/session/MobileNativeChatReasoningRow.tsx b/mobile/src/session/MobileNativeChatReasoningRow.tsx
index 2b17f6f866a..07a0ce9b832 100644
--- a/mobile/src/session/MobileNativeChatReasoningRow.tsx
+++ b/mobile/src/session/MobileNativeChatReasoningRow.tsx
@@ -1,5 +1,7 @@
+import { mobileNativeChatMemberId } from './MobileNativeChatScrollHold'
 import { useState } from 'react'
-import { Pressable, ScrollView, Text, View } from 'react-native'
+import { Pressable, Text, View } from 'react-native'
+import { MobileNativeChatOwnedScrollView } from './MobileNativeChatOwnedScrollView'
 import { Brain, ChevronRight } from 'lucide-react-native'
 import {
   nativeChatReasoningDisclosureKey,
@@ -43,7 +45,7 @@ export function MobileNativeChatReasoningRow({
   const headline = nativeChatReasoningHeadlineText(nativeChatReasoningHeadline(message, { live }))
   const label = nativeChatReasoningHeadlineText({ kind: 'reasoning' })
   return (
-    <View>
+    <View testID={mobileNativeChatMemberId(`thought:${message.id}`)}>
       <Pressable
         style={({ pressed }) => [styles.reasoningToggle, pressed && styles.reasoningPressed]}
         onPress={toggle}
@@ -63,6 +65,7 @@ export function MobileNativeChatReasoningRow({
       </Pressable>
       {expanded ? (
         <MobileNativeChatReasoningBody
+          positionKey={nativeChatReasoningDisclosureKey(message.id)}
           markdown={markdown}
           fontScale={fontScale}
           onOpenFile={onOpenFile}
@@ -76,18 +79,24 @@ export function MobileNativeChatReasoningRow({
 /** A reasoning block's text, under its row or the live activity line. Capped and scrollable, so an
  *  open block streaming at the tail cannot grow without bound. */
 export function MobileNativeChatReasoningBody({
+  positionKey,
   markdown,
   fontScale,
   onOpenFile,
   onLongPress
 }: {
+  positionKey: string
   markdown: string
   fontScale: number
   onOpenFile?: (relativePath: string) => void
   onLongPress?: () => void
 }): React.JSX.Element {
   return (
-    <ScrollView style={styles.reasoningBody} nestedScrollEnabled>
+    <MobileNativeChatOwnedScrollView
+      positionKey={positionKey}
+      style={styles.reasoningBody}
+      nestedScrollEnabled
+    >
       <MobileNativeChatLongPressContent onLongPress={onLongPress} style={styles.reasoning}>
         <MobileMarkdown
           content={markdown}
@@ -97,6 +106,6 @@ export function MobileNativeChatReasoningBody({
           onLongPress={onLongPress}
         />
       </MobileNativeChatLongPressContent>
-    </ScrollView>
+    </MobileNativeChatOwnedScrollView>
   )
 }
diff --git a/mobile/src/session/MobileNativeChatRowList.tsx b/mobile/src/session/MobileNativeChatRowList.tsx
new file mode 100644
index 00000000000..4952bca5303
--- /dev/null
+++ b/mobile/src/session/MobileNativeChatRowList.tsx
@@ -0,0 +1,69 @@
+import type { ComponentProps, ReactElement } from 'react'
+import { FlatList, Platform } from 'react-native'
+import type { MobileNativeChatRowKeys } from './mobile-native-chat-row-keys'
+import { MobileNativeChatPageList } from './MobileNativeChatPageList'
+import {
+  mobileNativeChatRowAnchor,
+  type MobileNativeChatTailFollow
+} from './use-mobile-native-chat-tail-follow'
+
+type PageProps = ComponentProps<typeof MobileNativeChatPageList>
+
+type Props = Pick<
+  PageProps,
+  | 'rows'
+  | 'roots'
+  | 'renderItem'
+  | 'rowState'
+  | 'layoutKey'
+  | 'contentContainerStyle'
+  | 'header'
+  | 'footer'
+  | 'emptyStateView'
+  | 'onScroll'
+> & {
+  tail: MobileNativeChatTailFollow
+  rowKeys: MobileNativeChatRowKeys
+  /** The native list's header; with one, the row below it anchors the visible content. */
+  nativeHeader: ReactElement | null
+  hasHeader: boolean
+}
+
+/** The chat's rows: the page draws its own keyed window, a native list recycles through FlatList. */
+export function MobileNativeChatRowList(props: Props): ReactElement {
+  const { tail, rowKeys, rows, renderItem, contentContainerStyle, onScroll, footer } = props
+  if (Platform.OS === 'web') {
+    const { roots, rowState, header, emptyStateView, layoutKey } = props
+    return (
+      <MobileNativeChatPageList
+        {...tail.pageListProps}
+        {...{ rows, rowKeys, roots, renderItem, rowState, contentContainerStyle }}
+        {...{ footer, emptyStateView, onScroll, header, layoutKey }}
+      />
+    )
+  }
+  return (
+    <FlatList
+      {...tail.listProps}
+      data={rows}
+      keyExtractor={rowKeys.keyOf}
+      renderItem={renderItem}
+      contentContainerStyle={contentContainerStyle}
+      // Let link/file taps land while the composer keyboard is up
+      // instead of being swallowed by the dismiss gesture.
+      keyboardShouldPersistTaps="handled"
+      onScroll={onScroll}
+      onScrollBeginDrag={tail.beginUserScroll}
+      onScrollEndDrag={tail.endUserDrag}
+      onMomentumScrollBegin={tail.beginMomentum}
+      onMomentumScrollEnd={tail.endMomentum}
+      scrollEventThrottle={32}
+      onContentSizeChange={tail.pinToTailAfterContentResize}
+      onLayout={tail.pinToTail}
+      maintainVisibleContentPosition={mobileNativeChatRowAnchor(props.hasHeader)}
+      ListHeaderComponent={props.nativeHeader}
+      ListFooterComponent={footer}
+      ListEmptyComponent={props.emptyStateView}
+    />
+  )
+}
diff --git a/mobile/src/session/MobileNativeChatScrollHold.test.tsx b/mobile/src/session/MobileNativeChatScrollHold.test.tsx
deleted file mode 100644
index 22cb607d60d..00000000000
--- a/mobile/src/session/MobileNativeChatScrollHold.test.tsx
+++ /dev/null
@@ -1,114 +0,0 @@
-import { createElement } from 'react'
-import { act, create, type ReactTestRenderer } from 'react-test-renderer'
-import { afterEach, describe, expect, it, vi } from 'vitest'
-import { MobileNativeChatScrollHold } from './MobileNativeChatScrollHold'
-
-const platform = vi.hoisted(() => ({ OS: 'web' }))
-
-vi.mock('react-native', () => ({ Platform: platform }))
-
-type Row = {
-  isConnected: boolean
-  children: Row[]
-  getBoundingClientRect: () => { top: number; bottom: number }
-}
-
-/** A row 100 tall whose top is `tops[0]` when first measured and `tops[1]` from then on. */
-function row(tops: number[], children: Row[] = []): Row {
-  const answers = [...tops]
-  return {
-    isConnected: true,
-    children,
-    getBoundingClientRect: () => {
-      const top = answers.length > 1 ? (answers.shift() ?? 0) : answers[0]
-      return { top, bottom: top + 100 }
-    }
-  }
-}
-
-/** A 600 tall view, 40 from the top of its content, over the given header block and list rows. */
-function scrollerOver(headerRows: Row[], listRows: Row[]) {
-  const header = row([-40], headerRows)
-  const heights = [1_000, 3_500]
-  const node = {
-    scrollTop: 40,
-    // Grows by 2,500 where 2,000 lands above the reader: live output lands below in the same update.
-    get scrollHeight(): number {
-      return heights.length > 1 ? (heights.shift() ?? 0) : heights[0]
-    },
-    getBoundingClientRect: () => ({ top: 0, bottom: 600 }),
-    firstElementChild: row([-40], [header, ...listRows])
-  }
-  return { node, listRef: { current: { getScrollableNode: () => node } } }
-}
-
-describe('MobileNativeChatScrollHold', () => {
-  let renderer: ReactTestRenderer | null = null
-
-  async function show(headKey: string, listRef: ReturnType<typeof scrollerOver>['listRef']) {
-    const element = createElement(MobileNativeChatScrollHold, { headKey, listRef })
-    await act(async () => {
-      if (renderer) {
-        renderer.update(element)
-      } else {
-        renderer = create(element)
-      }
-    })
-  }
-
-  afterEach(() => {
-    act(() => renderer?.unmount())
-    renderer = null
-    platform.OS = 'web'
-  })
-
-  it('moves by what landed above the reader, not by live output landing below it too', async () => {
-    const onScreen = row([300, 2_300])
-    const { node, listRef } = scrollerOver([], [row([100, 2_100]), onScreen, row([700, 3_200])])
-    await show('a', listRef)
-
-    await show('older', listRef)
-
-    expect(node.scrollTop).toBe(2_040)
-  })
-
-  it('holds a reader who is inside the loaded history, above the list’s own rows', async () => {
-    const control = row([-40])
-    const { node, listRef } = scrollerOver([control, row([200, 2_200])], [row([900, 2_900])])
-    await show('a', listRef)
-
-    await show('older', listRef)
-
-    expect(node.scrollTop).toBe(2_040)
-  })
-
-  it('leaves the view alone when the row it was holding is gone', async () => {
-    const onScreen = row([300, 2_300])
-    const { node, listRef } = scrollerOver([], [onScreen])
-    await show('a', listRef)
-    onScreen.isConnected = false
-
-    await show('older', listRef)
-
-    expect(node.scrollTop).toBe(40)
-  })
-
-  it('leaves the view alone while the first row is the same', async () => {
-    const { node, listRef } = scrollerOver([], [row([300, 2_300])])
-    await show('a', listRef)
-
-    await show('a', listRef)
-
-    expect(node.scrollTop).toBe(40)
-  })
-
-  it('does nothing in a native build, where the list holds its own place', async () => {
-    platform.OS = 'ios'
-    const { node, listRef } = scrollerOver([], [row([300, 2_300])])
-    await show('a', listRef)
-
-    await show('older', listRef)
-
-    expect(node.scrollTop).toBe(40)
-  })
-})
diff --git a/mobile/src/session/MobileNativeChatScrollHold.tsx b/mobile/src/session/MobileNativeChatScrollHold.tsx
index dac6254ac6d..a4f57370863 100644
--- a/mobile/src/session/MobileNativeChatScrollHold.tsx
+++ b/mobile/src/session/MobileNativeChatScrollHold.tsx
@@ -1,70 +1,268 @@
 import { Component, type RefObject } from 'react'
 import { Platform } from 'react-native'
+import { scrollWritesStopMomentum } from './mobile-native-chat-page-motion'
+import type { MobileNativeChatRowKeys } from './mobile-native-chat-row-keys'
+import {
+  mobileNativeChatReadingParts,
+  mobileNativeChatScrollRootKey,
+  type MobileNativeChatScrollRoots
+} from './mobile-native-chat-scroll-roots'
 
 type Box = { top: number; bottom: number }
 
 /** The parts of a DOM element this reads; on the page the list's scrollable node is one. */
-type RowElement = {
-  isConnected: boolean
+type Tagged = {
   getBoundingClientRect: () => Box
-  children: ArrayLike<RowElement>
-}
-type Scroller = {
-  scrollTop: number
-  getBoundingClientRect: () => Box
-  firstElementChild: RowElement | null
+  getAttribute: (name: string) => string | null
+  querySelectorAll: (selector: string) => ArrayLike<Tagged>
 }
+type Scroller = Tagged & { scrollTop: number; scrollHeight: number; clientHeight: number }
+export type MobileNativeChatScrollNode = Scroller
 
-type Held = { row: RowElement; top: number }
+/** Part of what the reader sees: a tool line or its run (`member`), else a row; where it was, and
+ *  the message that placed its row. */
+type Unit = { key: string; top: number; member?: string; placed: string }
 
 type Props = {
-  /** The first row's key: a change in it is rows changing above the reader. */
-  headKey: string | undefined
-  listRef: RefObject<{ getScrollableNode: () => Scroller | null | undefined } | null>
+  children?: React.ReactNode
+  roots?: MobileNativeChatScrollRoots
+  runPlacements?: ReadonlyMap<string, string>
+  rowKeys: Pick<MobileNativeChatRowKeys, 'scope' | 'sourceHead' | 'current' | 'placement'>
+  /** How rows draw (tools shown, text size); a change regroups and re-lays them like a new source. */
+  layoutKey?: string
+  /** Whether the reader follows the end, which then owns the scroll. */
+  isFollowing: () => boolean
+  /** On the page, the list makes the correction (`keepInPlace`), mid-scroll only for a regroup. */
+  listRef: RefObject<{
+    getScrollableNode: () => Scroller | null | undefined
+    keepInPlace?: (drift: number, regrouped: boolean) => void
+    holdPlace?: (on: boolean) => void
+  } | null>
 }
 
-/** The lowest row on screen. Why the lowest: the "Load earlier" control stays at the top while
- *  history lands under it, so the topmost element does not move with the rows. */
-function lowestRowOnScreen(scroller: Scroller): Held | null {
-  const content = scroller.firstElementChild
-  if (!content) {
-    return null
+const ROW = 'chat-row:'
+const MEMBER = 'chat-member:'
+
+/** A message row's `testID`, which the page draws as `data-testid`. It sets message rows apart from
+ *  the "Load earlier" control and the live status line, which don't move with the messages. */
+export function mobileNativeChatRowId(key: string): string {
+  return `${ROW}${key}`
+}
+
+/** A tool line's `testID`, by its line identity, or the run's, inside a row. */
+export function mobileNativeChatMemberId(id: string): string {
+  return `${MEMBER}${id}`
+}
+
+/** Tagged elements in document order; ids are compared, never put in a selector. */
+function tagged(node: Tagged, prefix: string): { id: string; node: Tagged }[] {
+  return Array.from(node.querySelectorAll(`[data-testid^="${prefix}"]`), (element) => ({
+    id: element.getAttribute('data-testid')?.slice(prefix.length) ?? '',
+    node: element
+  }))
+}
+
+function onScreen(box: Box, view: Box): boolean {
+  return box.bottom > view.top && box.top < view.bottom
+}
+
+/** A row's tool lines on screen, else its run when the run's top is (below that top, lines can join
+ *  or leave), else the row itself. */
+function unitsOf(row: Tagged, view: Box, self: Unit): Unit[] {
+  const shown: Unit[] = []
+  const parts =
+    typeof Element !== 'undefined' && row instanceof Element
+      ? mobileNativeChatReadingParts(row).map((node) => ({
+          node,
+          id:
+            mobileNativeChatScrollRootKey(node) !== undefined
+              ? `root:${mobileNativeChatScrollRootKey(node)}`
+              : (node.getAttribute('data-testid')?.slice(MEMBER.length) ?? '')
+        }))
+      : tagged(row, MEMBER)
+  for (const { id, node } of parts) {
+    const box = node.getBoundingClientRect()
+    if (box.top >= view.bottom) {
+      break
+    }
+    if (id === 'run' ? box.top >= view.top : onScreen(box, view)) {
+      shown.push({ ...self, top: box.top, member: id })
+    }
   }
+  const lines = shown.filter((unit) => unit.member !== 'run')
+  return lines.length > 0 ? lines : [shown[0] ?? self]
+}
+
+/** What the reader is reading, in page order. */
+function placeOnScreen(scroller: Scroller, { placement }: Props['rowKeys']): Unit[] {
   const view = scroller.getBoundingClientRect()
-  // The list's own rows, then the rows of the header block that precedes them.
-  const header = content.children[0]
-  for (const rows of [content.children, header?.children ?? []]) {
-    for (let at = rows.length - 1; at >= 0; at -= 1) {
-      const box = rows[at].getBoundingClientRect()
-      if (box.top < view.bottom && box.bottom > view.top && rows[at] !== header) {
-        return { row: rows[at], top: box.top }
+  const rows = tagged(scroller, ROW)
+  // Rows in normal flow have ordered bottoms, so the first one on screen is found without
+  // measuring the up to 2,000 above it.
+  let low = 0
+  let high = rows.length
+  while (low < high) {
+    const middle = low + Math.floor((high - low) / 2)
+    if (rows[middle]!.node.getBoundingClientRect().bottom <= view.top) {
+      low = middle + 1
+    } else {
+      high = middle
+    }
+  }
+  let end = low
+  while (end < rows.length && rows[end]!.node.getBoundingClientRect().top < view.bottom) {
+    end += 1
+  }
+  const self = ({ id, node }: { id: string; node: Tagged }): Unit => {
+    return { key: id, top: node.getBoundingClientRect().top, placed: placement(id) }
+  }
+  const units = rows.slice(low, end).flatMap((row) => unitsOf(row.node, view, self(row)))
+  // The nearest rows off screen stand in when the update takes away all that was on it.
+  return units.concat([rows[end], rows[low - 1]].flatMap((row) => (row ? [self(row)] : [])))
+}
+
+/** Where a held part is drawn now, if the update kept it. A line in the row now drawing its old
+ *  row's messages (an orphan result's line is its call's once paired); a run only in the row that
+ *  kept its key; a row only while the same message places it, since a group keeps its key when the
+ *  fold moves it. */
+function drawn(
+  unit: Unit,
+  rows: Map<string, Tagged>,
+  keys: Props['rowKeys'],
+  roots?: MobileNativeChatScrollRoots
+): Tagged | undefined {
+  const { key, member } = unit
+  if (member?.startsWith('root:')) {
+    return roots?.frame(member.slice(5))
+  }
+  if (member === undefined) {
+    return keys.placement(key) === unit.placed ? rows.get(key) : undefined
+  }
+  const row = rows.get(member === 'run' ? key : (keys.current(key) ?? ''))
+  const paired = member.startsWith('result:') ? `call:${member.slice('result:'.length)}` : member
+  return row && tagged(row, MEMBER).find((m) => m.id === member || m.id === paired)?.node
+}
+
+/** The update moves what the reader reads to another row (a line to another group, a row placed by
+ *  another message): the browser's anchoring loses that node, so the hold puts it back. */
+function moves(
+  unit: Unit | undefined,
+  keys: Props['rowKeys'],
+  placements?: ReadonlyMap<string, string>,
+  roots?: MobileNativeChatScrollRoots
+): boolean {
+  if (!unit) {
+    return false
+  }
+  if (unit.member === undefined) {
+    return keys.placement(unit.key) !== unit.placed
+  }
+  if (unit.member.startsWith('root:')) {
+    const owner = roots?.owner(unit.member.slice(5))
+    const now = owner === undefined ? undefined : placements?.get(owner)
+    return now !== undefined && now !== unit.placed
+  }
+  // An orphan result's line goes to its call's row once the call lands, and its old row stays.
+  return (
+    unit.member.startsWith('result:') ||
+    (unit.member !== 'run' && keys.current(unit.key) !== unit.key)
+  )
+}
+
+/** iOS is still bouncing the list past an end. A write then lands while WebKit owns the scroll, and
+ *  the list stops taking the reader's scrolls until they leave the chat. */
+function overscrolled({ scrollTop, scrollHeight, clientHeight }: Scroller): boolean {
+  return scrollTop < 0 || scrollTop > scrollHeight - clientHeight + 1
+}
+
+/** Keeps a parked reader's place on the page when the source window changes above them (an older
+ *  page, a cap trim) or the rows regroup (Tools, text size): the first part of what they were reading that the update kept goes back where
+ *  it was. Where the browser has scroll anchoring it keeps the place through ordinary changes, so the
+ *  hold runs only for a regroup or a move to another row, with the browser's anchoring off from
+ *  before the update until its correction. A following reader is left to the follow owner, which
+ *  holds the end. A class because only `getSnapshotBeforeUpdate` sees the rows before the update is
+ *  in the document. A native list holds its own place (`maintainVisibleContentPosition`). */
+export class MobileNativeChatScrollHold extends Component<Props> {
+  getSnapshotBeforeUpdate(previous: Props): Unit[] | null {
+    const regrouped = previous.layoutKey !== this.props.layoutKey
+    const moved = new Set(
+      Array.from(previous.runPlacements ?? []).flatMap(([owner, row]) =>
+        this.props.runPlacements?.get(owner) !== row ? [owner] : []
+      )
+    )
+    if (Platform.OS === 'web' && previous.rowKeys.scope === this.props.rowKeys.scope) {
+      this.props.roots?.capture(moved, regrouped)
+    }
+    // Another chat opens at its end, which the follow owner resets only after this reads it.
+    if (
+      Platform.OS !== 'web' ||
+      previous.rowKeys.scope !== this.props.rowKeys.scope ||
+      (previous.rowKeys.sourceHead === this.props.rowKeys.sourceHead &&
+        !regrouped &&
+        moved.size === 0) ||
+      this.props.isFollowing()
+    ) {
+      return null
+    }
+    const list = this.props.listRef.current
+    const scroller = list?.getScrollableNode()
+    const held =
+      scroller && !overscrolled(scroller) ? placeOnScreen(scroller, previous.rowKeys) : null
+    if (
+      !held ||
+      (!scrollWritesStopMomentum() &&
+        !regrouped &&
+        !moves(held[0], this.props.rowKeys, this.props.runPlacements, this.props.roots))
+    ) {
+      return null
+    }
+    list?.holdPlace?.(true)
+    return held
+  }
+
+  componentDidMount(): void {
+    this.props.roots?.restoreAll()
+  }
+
+  componentDidUpdate(previous: Props, _state: unknown, held: Unit[] | null): void {
+    try {
+      const regrouped = previous.layoutKey !== this.props.layoutKey
+      this.props.roots?.restoreAll(regrouped, false)
+      if (held) {
+        this.restore(held, regrouped)
+      }
+    } finally {
+      this.props.roots?.releaseHold()
+      // Whatever the correction did, the scroll goes back to its owner.
+      if (held) {
+        this.props.listRef.current?.holdPlace?.(false)
       }
     }
   }
-  return null
-}
 
-/** Keeps the page's view on the same rows when rows above it change, by putting a row that was on
- *  screen back where it was. A class because only `getSnapshotBeforeUpdate` sees that row before
- *  the new ones are in the document. A native list holds its own place
- *  (`maintainVisibleContentPosition`). */
-export class MobileNativeChatScrollHold extends Component<Props> {
-  getSnapshotBeforeUpdate(previous: Props): Held | null {
-    if (Platform.OS !== 'web' || previous.headKey === this.props.headKey) {
-      return null
+  private restore(held: Unit[], regrouped: boolean): void {
+    const list = this.props.listRef.current
+    const scroller = held.length ? list?.getScrollableNode() : null
+    if (!scroller) {
+      return
     }
-    const scroller = this.props.listRef.current?.getScrollableNode()
-    return scroller ? lowestRowOnScreen(scroller) : null
-  }
-
-  componentDidUpdate(_previous: Props, _state: unknown, held: Held | null): void {
-    const scroller = held?.row.isConnected ? this.props.listRef.current?.getScrollableNode() : null
-    if (held && scroller) {
-      scroller.scrollTop += held.row.getBoundingClientRect().top - held.top
+    const rows = new Map(tagged(scroller, ROW).map(({ id, node }) => [id, node]))
+    for (const unit of held) {
+      const node = drawn(unit, rows, this.props.rowKeys, this.props.roots)
+      if (node) {
+        const drift = node.getBoundingClientRect().top - unit.top
+        // Sub-pixel drift is layout noise; a write would stop iOS momentum for nothing.
+        if (Math.abs(drift) >= 0.5 && list?.keepInPlace) {
+          list.keepInPlace(drift, regrouped)
+        } else if (Math.abs(drift) >= 0.5) {
+          scroller.scrollTop += drift
+        }
+        return
+      }
     }
   }
 
-  render(): null {
-    return null
+  render(): React.ReactNode {
+    return this.props.children ?? null
   }
 }
diff --git a/mobile/src/session/MobileNativeChatTaskList.tsx b/mobile/src/session/MobileNativeChatTaskList.tsx
index 627f0ea6a24..7caa254c9af 100644
--- a/mobile/src/session/MobileNativeChatTaskList.tsx
+++ b/mobile/src/session/MobileNativeChatTaskList.tsx
@@ -1,4 +1,3 @@
-import { useState } from 'react'
 import { Pressable, Text, View } from 'react-native'
 import { ChevronRight, Circle, CircleCheck, CircleDot, ListChecks } from 'lucide-react-native'
 import {
@@ -12,6 +11,7 @@ import {
 import { colors } from '../theme/mobile-theme'
 import { useMobileNativeChatOpenedDetail } from './mobile-native-chat-opened-detail'
 import { toolStyles as styles, toolType } from './mobile-native-chat-tool-styles'
+import { useMobileNativeChatDisclosure } from './mobile-native-chat-disclosure-store'
 
 const STATUS_WORD: Record<NativeChatTask['status'], string> = {
   completed: NATIVE_CHAT_TASK_LIST_COPY.completed,
@@ -83,13 +83,21 @@ function Checklist({ list, fontScale }: { list: TaskList; fontScale: number }) {
 }
 
 /** The whole list behind a disclosure, under a list of what changed. */
-function FullList({ list, fontScale }: { list: TaskList; fontScale: number }) {
-  const [open, setOpen] = useState(false)
+function FullList({
+  list,
+  fontScale,
+  disclosureKey
+}: {
+  list: TaskList
+  fontScale: number
+  disclosureKey?: string
+}) {
+  const [open, setOpen] = useMobileNativeChatDisclosure(disclosureKey, false)
   return (
     <View>
       <Pressable
         style={styles.taskDisclosure}
-        onPress={() => setOpen((value) => !value)}
+        onPress={() => setOpen(!open)}
         accessibilityRole="button"
         accessibilityState={{ expanded: open }}
       >
@@ -119,11 +127,13 @@ function OpenedChecklist({ list, fontScale }: { list: TaskList; fontScale: numbe
 export function MobileNativeChatTaskList({
   list,
   previous,
-  fontScale
+  fontScale,
+  disclosureKey
 }: {
   list: TaskList
   previous?: TaskList
   fontScale: number
+  disclosureKey?: string
 }): React.JSX.Element {
   const completed = list.tasks.filter((task) => task.status === 'completed').length
   const changes = previous ? diffNativeChatTaskLists(previous, list) : null
@@ -163,7 +173,7 @@ export function MobileNativeChatTaskList({
           ) : (
             <Text style={[styles.lineMeta, type.meta]}>{NATIVE_CHAT_TASK_LIST_COPY.unchanged}</Text>
           )}
-          <FullList list={list} fontScale={fontScale} />
+          <FullList list={list} fontScale={fontScale} disclosureKey={disclosureKey} />
         </>
       ) : (
         <Checklist list={list} fontScale={fontScale} />
diff --git a/mobile/src/session/MobileNativeChatToolLine.tsx b/mobile/src/session/MobileNativeChatToolLine.tsx
index 05ce18f8a4b..d76bf9a9d66 100644
--- a/mobile/src/session/MobileNativeChatToolLine.tsx
+++ b/mobile/src/session/MobileNativeChatToolLine.tsx
@@ -1,5 +1,6 @@
 import { useMemo } from 'react'
-import { Pressable, ScrollView, Text, View } from 'react-native'
+import { Pressable, Text, View } from 'react-native'
+import { MobileNativeChatOwnedScrollView } from './MobileNativeChatOwnedScrollView'
 import { ChevronRight } from 'lucide-react-native'
 import { agentJournalToolCallLifecycle } from '../../../src/shared/agent-journal-tool-call-lifecycle'
 import { diffFromText, diffFromToolCall } from '../../../src/shared/native-chat-diff'
@@ -92,7 +93,9 @@ function ToolLineDetail({
   fullCommand,
   commandLanguage,
   results,
-  fontScale
+  fontScale,
+  disclosureKey,
+  memberId
 }: {
   call: NativeChatToolCallBlock | undefined
   body: NativeChatToolResultBlock | undefined
@@ -100,6 +103,8 @@ function ToolLineDetail({
   commandLanguage: string | null
   results: NativeChatWebSearchResult[]
   fontScale: number
+  disclosureKey?: string
+  memberId?: string
 }): React.JSX.Element {
   const diff = call
     ? diffFromToolCall(call.name, call.input)
@@ -120,7 +125,9 @@ function ToolLineDetail({
       {results.length > 0 ? <SearchResults results={results} fontScale={fontScale} /> : null}
       {diff ? <DiffView lines={diff} fontScale={fontScale} /> : null}
       {!diff && fullCommand ? (
-        <ScrollView
+        <MobileNativeChatOwnedScrollView
+          rootIdentity={`${memberId ?? call?.callId ?? 'detail'}:command`}
+          positionKey={`${disclosureKey ?? call?.callId ?? 'detail'}:command`}
           style={[styles.codeBox, styles.codeScroll]}
           nestedScrollEnabled
           keyboardShouldPersistTaps="handled"
@@ -128,10 +135,12 @@ function ToolLineDetail({
           <Text selectable={INLINE_TEXT_SELECTION} style={[styles.codeText, type]}>
             {command ? <MobileSyntaxSegments segments={command} /> : fullCommand}
           </Text>
-        </ScrollView>
+        </MobileNativeChatOwnedScrollView>
       ) : null}
       {body ? (
-        <ScrollView
+        <MobileNativeChatOwnedScrollView
+          rootIdentity={`${memberId ?? body?.callId ?? 'detail'}:output`}
+          positionKey={`${disclosureKey ?? body?.callId ?? 'detail'}:output`}
           style={[styles.codeBox, styles.codeScroll]}
           nestedScrollEnabled
           keyboardShouldPersistTaps="handled"
@@ -142,7 +151,7 @@ function ToolLineDetail({
           >
             {truncateToolDetail(body.output)}
           </Text>
-        </ScrollView>
+        </MobileNativeChatOwnedScrollView>
       ) : null}
     </View>
   )
@@ -151,6 +160,7 @@ function ToolLineDetail({
 /** Desktop parity: `NativeChatToolLine`. A tool sentence with its output behind its
  *  own disclosure; an orphan result draws as a `Result` row. */
 export function MobileNativeChatToolLine({
+  memberId,
   block,
   result,
   defaultExpanded,
@@ -158,6 +168,8 @@ export function MobileNativeChatToolLine({
   fontScale,
   onOpenFile
 }: {
+  /** Tags the line for the page's place-hold. */
+  memberId?: string
   block: NativeChatToolCallBlock | NativeChatToolResultBlock
   /** This call's output, when the run paired one to it. */
   result?: NativeChatToolResultBlock
@@ -198,7 +210,7 @@ export function MobileNativeChatToolLine({
   const duration = call ? formatToolDuration(call.durationMs) : null
 
   return (
-    <View>
+    <View testID={memberId}>
       <Pressable
         style={styles.line}
         onPress={() => hasDetail && setExpanded(!expanded)}
@@ -248,6 +260,8 @@ export function MobileNativeChatToolLine({
       </Pressable>
       {hasDetail && expanded ? (
         <ToolLineDetail
+          memberId={memberId}
+          disclosureKey={disclosureKey}
           call={call}
           body={body}
           fullCommand={fullCommand}
diff --git a/mobile/src/session/MobileNativeChatToolRun.tsx b/mobile/src/session/MobileNativeChatToolRun.tsx
index 312edaa1969..465470c1f34 100644
--- a/mobile/src/session/MobileNativeChatToolRun.tsx
+++ b/mobile/src/session/MobileNativeChatToolRun.tsx
@@ -10,7 +10,8 @@ import {
 import {
   Animated,
   Pressable,
-  ScrollView,
+  Platform,
+  type ScrollView,
   Text,
   useWindowDimensions,
   View,
@@ -51,6 +52,13 @@ import {
   useMobileNativeChatDisclosure
 } from './mobile-native-chat-disclosure-store'
 import { toolStyles as styles, toolType } from './mobile-native-chat-tool-styles'
+import { mobileNativeChatMemberId } from './MobileNativeChatScrollHold'
+import { MobileNativeChatOwnedScrollView } from './MobileNativeChatOwnedScrollView'
+import type {
+  MobileNativeChatToolRunAsides,
+  MobileNativeChatToolRunProps
+} from './mobile-native-chat-tool-run-props'
+export type { MobileNativeChatToolRunAsides } from './mobile-native-chat-tool-run-props'
 
 /** Desktop's 18rem: an opened run lists this much before it scrolls in place. */
 const MEMBERS_MIN_HEIGHT = 288
@@ -94,13 +102,6 @@ function PulsingText({
   )
 }
 
-/** Desktop parity: `NativeChatToolRunAsides`. Rows drawn among an open run's lines, each keyed:
- *  before the block they are keyed by, or after the last. */
-export type MobileNativeChatToolRunAsides = {
-  before: ReadonlyMap<NativeChatBlock, readonly React.JSX.Element[]>
-  after: readonly React.JSX.Element[]
-}
-
 /** Desktop parity: `NativeChatToolRunMembers`. An opened run's members in a bounded
  *  box, so live work fills it instead of lengthening the chat. A live run opens on
  *  what it is doing now and follows it while the reader stays at the end. */
@@ -108,6 +109,7 @@ function ToolRunMembers({
   followKey,
   startsAtEnd,
   memoryKey,
+  owner,
   children
 }: {
   /** How much work the run holds: a reader at the end follows it growing. Opening a detail
@@ -116,10 +118,13 @@ function ToolRunMembers({
   startsAtEnd: boolean
   /** The run's disclosure key. The list recycles rows; the box comes back as the reader left it. */
   memoryKey?: string
+  owner?: string
   children: React.ReactNode
 }): React.JSX.Element {
   const { height } = useWindowDimensions()
-  const runScroll = useContext(MobileNativeChatDisclosureContext)?.runScroll
+  const store = useContext(MobileNativeChatDisclosureContext)
+  const runScroll = store?.runScroll
+  const owned = Platform.OS === 'web' && store !== null
   const [remembered] = useState(() =>
     memoryKey === undefined ? undefined : runScroll?.get(memoryKey)
   )
@@ -129,10 +134,10 @@ function ToolRunMembers({
   // Desktop's rule: follow when the work changes, and only if the reader was at the end before
   // it. Resolved here, with the update, so a later detail opening never inherits a follow.
   useLayoutEffect(() => {
-    if (followsEnd.current) {
+    if (!owned && followsEnd.current) {
       scroller.current?.scrollToEnd({ animated: false })
     }
-  }, [followKey])
+  }, [followKey, owned])
   const details = useRef(new Map<string, number>())
   const [openedHeight, setOpenedHeight] = useState(0)
   // Room for the list plus what the reader has opened in it, up to half the screen.
@@ -152,7 +157,7 @@ function ToolRunMembers({
     const { contentOffset, contentSize, layoutMeasurement } = nativeEvent
     followsEnd.current =
       contentSize.height - contentOffset.y - layoutMeasurement.height <= FOLLOW_REARM_PX
-    if (runScroll && memoryKey !== undefined) {
+    if (!owned && runScroll && memoryKey !== undefined) {
       runScroll.delete(memoryKey)
       runScroll.set(memoryKey, { top: contentOffset.y, followsEnd: followsEnd.current })
       if (runScroll.size > MAX_DISCLOSURES) {
@@ -165,14 +170,19 @@ function ToolRunMembers({
   }
   // The remembered offset needs the rows laid out first, which the box's first size reports.
   const onContentSizeChange = () => {
-    if (pendingRestore.current && remembered) {
+    if (!owned && pendingRestore.current && remembered) {
       pendingRestore.current = false
       scroller.current?.scrollTo({ y: remembered.top, animated: false })
     }
   }
   return (
     <MobileNativeChatOpenedDetailContext.Provider value={reportDetail}>
-      <ScrollView
+      <MobileNativeChatOwnedScrollView
+        positionKey={memoryKey ?? `run:${owner ?? 'local'}`}
+        rootIdentity={`run:${owner ?? 'local'}`}
+        owner={owner}
+        initialFollow={startsAtEnd}
+        followKey={followKey}
         ref={scroller}
         style={[
           styles.members,
@@ -186,7 +196,7 @@ function ToolRunMembers({
         onContentSizeChange={onContentSizeChange}
       >
         {children}
-      </ScrollView>
+      </MobileNativeChatOwnedScrollView>
     </MobileNativeChatOpenedDetailContext.Provider>
   )
 }
@@ -206,28 +216,7 @@ export function ToolRun({
   previousUpdatePlan,
   fontScale = 1,
   onOpenFile
-}: {
-  blocks: NativeChatBlock[]
-  /** The last plan each task-list tool wrote before this run, so an update reads as its changes. */
-  previousTodoWrite?: NativeChatToolCallBlock
-  previousUpdatePlan?: NativeChatToolCallBlock
-  defaultExpanded: boolean
-  /** The row this run belongs to. The list recycles rows, so what the reader opened is
-   *  remembered somewhere that outlives the row. */
-  disclosureId?: string
-  /** Rows drawn among the run's lines, each before the block it is keyed by, or after the last. */
-  asides?: MobileNativeChatToolRunAsides
-  /** Every line's default: open under the Tools toggle. */
-  expandChildren: boolean
-  /** Structured lifecycle state; keeps an orphaned running call from spinning. */
-  activeTurnIsWorking?: boolean
-  /** Whether this run is the working turn's last. Only that run is live. */
-  trailing?: boolean
-  /** The turn is blocked on the reader's answer, so its calls decide liveness. */
-  awaitingAnswer?: boolean
-  fontScale?: number
-  onOpenFile?: (path: string) => void
-}): React.JSX.Element {
+}: MobileNativeChatToolRunProps): React.JSX.Element {
   // A reader's choice belongs to the default it deviated from, so toggling the Tools
   // default back restores it.
   const runKey = disclosureId === undefined ? undefined : `run:${disclosureId}:${defaultExpanded}`
@@ -271,7 +260,7 @@ export function ToolRun({
   const iconSize = 15 * fontScale
 
   return (
-    <View style={styles.run}>
+    <View style={styles.run} testID={mobileNativeChatMemberId('run')}>
       {/* One element for the run's whole life: live and settled are states of this
           button, not two buttons. */}
       <Pressable
@@ -311,6 +300,7 @@ export function ToolRun({
           followKey={blocks.length + asideCount}
           startsAtEnd={live}
           memoryKey={runKey}
+          owner={disclosureId}
         >
           <ToolRunMemberList
             blocks={blocks}
@@ -360,26 +350,40 @@ function ToolRunMemberList({
   const { editCards, consumedResults } = useMemo(() => buildEditCards(blocks), [blocks])
   const { resultByCall, pairedResults } = useMemo(() => pairNativeChatToolResults(blocks), [blocks])
   const seen = new Map<string, number>()
-  const member = (block: NativeChatBlock, blockIndex: number): React.ReactNode => {
+  // Each drawn member's line identity: the page's place-hold finds it by this, and a card keyed by
+  // it keeps its state when older calls join the run above it.
+  const memberSeen = new Map<string, number>()
+  const memberIdentity = (block: NativeChatBlock) =>
+    nativeChatToolLineIdentity(block, memberSeen, true)
+  const member = (block: NativeChatBlock): React.ReactNode => {
     const taskList = taskLists.rows.get(block)
     if (taskList) {
+      const id = memberIdentity(block)
       return (
-        <MobileNativeChatTaskList key={`tasks:${blockIndex}`} {...taskList} fontScale={fontScale} />
+        <View key={`tasks:${id}`} testID={mobileNativeChatMemberId(id)}>
+          <MobileNativeChatTaskList
+            {...taskList}
+            fontScale={fontScale}
+            disclosureKey={disclosureId === undefined ? undefined : `tasks:${disclosureId}:${id}`}
+          />
+        </View>
       )
     }
     const edit = editCards.get(block)
     if (edit) {
+      const id = memberIdentity(block)
       return (
-        <View key={`edit:${edit.key}`}>
+        <View key={`edit:${id}`} testID={mobileNativeChatMemberId(id)}>
           {edit.files.map((file, fileIndex) => (
             <MobileNativeChatDiffCard
-              key={`${edit.key}:${fileIndex}`}
+              key={`${id}:${fileIndex}`}
               file={file}
+              rootIdentity={`diff:${id}:${fileIndex}`}
               defaultExpanded={expandChildren}
               disclosureKey={
                 disclosureId === undefined
                   ? undefined
-                  : `diff:${disclosureId}:${expandChildren}:${edit.key}:${fileIndex}`
+                  : `diff:${disclosureId}:${expandChildren}:${id}:${fileIndex}`
               }
               fontScale={fontScale}
               onOpenFile={onOpenFile}
@@ -401,6 +405,7 @@ function ToolRunMemberList({
     return (
       <MobileNativeChatToolLine
         key={lineIdentity}
+        memberId={mobileNativeChatMemberId(memberIdentity(block))}
         block={block}
         result={block.type === 'tool-call' ? resultByCall.get(block) : undefined}
         defaultExpanded={expandChildren}
@@ -418,10 +423,7 @@ function ToolRunMemberList({
   return (
     <>
       {/* One flat keyed list with or without asides, so a row gaining its first never remounts a line. */}
-      {blocks.flatMap((block, blockIndex) => [
-        ...(asides?.before.get(block) ?? []),
-        member(block, blockIndex)
-      ])}
+      {blocks.flatMap((block) => [...(asides?.before.get(block) ?? []), member(block)])}
       {asides?.after}
     </>
   )
diff --git a/mobile/src/session/MobileNativeChatView.harness.test-fixture.ts b/mobile/src/session/MobileNativeChatView.harness.test-fixture.ts
index 617e9147405..92bd95df52c 100644
--- a/mobile/src/session/MobileNativeChatView.harness.test-fixture.ts
+++ b/mobile/src/session/MobileNativeChatView.harness.test-fixture.ts
@@ -75,7 +75,8 @@ export function installChatViewHooks(): void {
     renderer = null
     scrollToEnd.mockReset()
     scrollToOffset.mockReset()
-    pageScroller.scrollHeight = 0
+    Object.assign(pageScroller, { scrollTop: 0, scrollHeight: 0, clientHeight: 500 })
+    pageScroller.style.overflowAnchor = ''
     vi.unstubAllGlobals()
   })
 }
@@ -141,6 +142,17 @@ export async function pressSend(): Promise<void> {
   })
 }
 
+/** What the list reports from a scroll, drag or momentum event, in a 500-tall viewport. */
+export function scrollEvent(y: number, contentHeight: number) {
+  return {
+    nativeEvent: {
+      contentOffset: { y },
+      contentSize: { height: contentHeight },
+      layoutMeasurement: { height: 500 }
+    }
+  }
+}
+
 export async function scrollAwayFromTail(): Promise<void> {
   await act(async () => {
     list().props.onScrollBeginDrag?.({})
diff --git a/mobile/src/session/MobileNativeChatView.history-paging.test.ts b/mobile/src/session/MobileNativeChatView.history-paging.test.ts
index 02d061e5d2d..7caf12ef675 100644
--- a/mobile/src/session/MobileNativeChatView.history-paging.test.ts
+++ b/mobile/src/session/MobileNativeChatView.history-paging.test.ts
@@ -3,11 +3,13 @@ import { describe, expect, it, vi, beforeEach, afterEach } from 'vitest'
 import {
   installChatViewHooks,
   assistantTurn,
+  hostType,
   list,
   pageScroller,
   platform,
   render,
   root,
+  scrollEvent,
   scrollToEnd,
   scrollToOffset,
   update
@@ -132,8 +134,30 @@ describe('MobileNativeChatView: history paging and anchoring', () => {
   })
 
   describe('on the page, where the list reports no drag or momentum', () => {
+    const observers = new Set<(entries: unknown[]) => void>()
+    // The browser's resize step, before paint; RN Web's size report comes a task later.
+    const resized = () => act(() => observers.forEach((deliver) => deliver([])))
+    const page = () => root().find((node) => hostType(node) === 'ScrollView')
+    const loadEarlier = () =>
+      root().find(
+        (node) =>
+          hostType(node) === 'Pressable' &&
+          node.findAll((text) => text.props.children === 'Load earlier messages').length > 0
+      )
+
     beforeEach(() => {
       platform.OS = 'web'
+      scrollToOffset.mockImplementation((to: { offset: number }) => {
+        pageScroller.scrollTop = to.offset
+      })
+      observers.clear()
+      vi.stubGlobal('ResizeObserver', function (deliver: (entries: unknown[]) => void) {
+        return {
+          observe: () => observers.add(deliver),
+          unobserve: () => {},
+          disconnect: () => observers.delete(deliver)
+        }
+      })
     })
 
     afterEach(() => {
@@ -141,77 +165,199 @@ describe('MobileNativeChatView: history paging and anchoring', () => {
     })
 
     function scrolledTo(y: number, contentHeight: number) {
-      return {
-        nativeEvent: {
-          contentOffset: { y },
-          contentSize: { height: contentHeight },
-          layoutMeasurement: { height: 500 }
-        }
-      }
+      Object.assign(pageScroller, { scrollTop: y, scrollHeight: contentHeight })
+      return scrollEvent(y, contentHeight)
     }
 
-    it('stops following when the reader scrolls up, and resumes at the end', async () => {
-      await render({ folded: [assistantTurn('a1', 'Latest')] })
+    // RN Web's report and the scroller's own event, for one position.
+    function scrollTo(y: number, contentHeight: number) {
       act(() => {
-        list().props.onContentSizeChange(320, 1_000)
-        list().props.onScroll(scrolledTo(500, 1_000))
+        page().props.onScroll(scrolledTo(y, contentHeight))
+        pageScroller.scroll()
       })
-      scrollToOffset.mockClear()
+    }
 
-      // No drag event arrives on the page: the move up is all there is to go on.
-      act(() => {
-        list().props.onScroll(scrolledTo(300, 1_000))
-        list().props.onContentSizeChange(320, 1_200)
-      })
-      expect(scrollToOffset).not.toHaveBeenCalled()
+    it('holds a following reader at the live end through growth and a smaller viewport', async () => {
+      const latest = [assistantTurn('a1', 'Latest')]
+      const landed = [assistantTurn('a0', 'Older'), ...latest]
+      const onLoadEarlier = vi.fn()
+      await render({ folded: latest, hasMore: true, onLoadEarlier })
+      scrollTo(500, 1_000)
+
+      // Older rows land; the observer pins before paint.
+      act(() => loadEarlier().props.onPress())
+      await update({ folded: landed, hasMore: true, onLoadEarlier })
+      pageScroller.scrollHeight = 5_000
+      resized()
+      expect(onLoadEarlier).toHaveBeenCalledOnce()
+      expect(scrollToOffset).toHaveBeenCalledOnce()
+      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 4_500 })
+
+      // The pin's own move, short of a reply that grew meanwhile, is not the reader's.
+      scrollTo(4_500, 5_400)
+      resized()
+      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 4_900 })
+
+      // The browser clamping the scroll to a shorter end is layout's, not the reader's: it still
+      // follows, and the next growth pins.
+      scrollTo(3_500, 4_000)
+      pageScroller.scrollHeight = 5_400
+      resized()
+      expect(scrollToOffset).toHaveBeenCalledTimes(3)
+      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 4_900 })
+      scrollTo(4_900, 5_400)
+
+      // The reader's wheel moves it up: it leaves the end.
+      pageScroller.input('wheel')
+      scrollTo(3_000, 5_400)
+      pageScroller.scrollHeight = 6_000
+      resized()
+      expect(scrollToOffset).toHaveBeenCalledTimes(3)
       expect(
         root().findAll((node) => node.props.accessibilityLabel === 'Scroll to latest')
       ).toHaveLength(1)
 
-      act(() => {
-        list().props.onScroll(scrolledTo(700, 1_200))
-        list().props.onContentSizeChange(320, 1_400)
-      })
-      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 1_400 })
+      // Back at the end it follows again, and a smaller viewport pins to the live end.
+      scrollTo(5_500, 6_000)
+      pageScroller.scrollHeight = 6_400
+      resized()
+      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 5_900 })
+      pageScroller.clientHeight = 300
+      resized()
+      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 6_100 })
+      expect(scrollToEnd).not.toHaveBeenCalled()
     })
 
-    it('does not take its own pin, landing short of a grown end, for the reader', async () => {
-      await render({ folded: [assistantTurn('a1', 'Latest')] })
-      act(() => {
-        list().props.onContentSizeChange(320, 1_000)
-        list().props.onScroll(scrolledTo(500, 1_000))
-      })
-      scrollToOffset.mockClear()
-
-      // The pin reached the end it was sent to; the reply had grown 400 past it by then.
-      act(() => {
-        list().props.onScroll(scrolledTo(700, 1_600))
-        list().props.onContentSizeChange(320, 1_600)
-      })
-
-      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 1_600 })
+    it('resumes an expired downward fling near the end, preserving small upward detachment', async () => {
+      const now = vi.spyOn(Date, 'now').mockReturnValue(10_000)
+      vi.stubGlobal('navigator', { userAgent: 'Chrome' })
+      const browserHolds = () => pageScroller.style.overflowAnchor === 'auto'
+      await render({ folded: ['a1', 'a2', 'a3'].map((id) => assistantTurn(id, id)) })
+      scrollTo(500, 1_000)
+      resized()
+      pageScroller.input('wheel')
+      scrollTo(497, 1_000)
+      // Expired input and geometry away from the end cannot detach or attach by themselves.
+      now.mockReturnValue(11_100)
+      pageScroller.scrollHeight = 1_200
+      resized()
+      expect(browserHolds()).toBe(true)
+      scrollTo(632, 1_200)
+      expect(browserHolds()).toBe(false)
+      pageScroller.scrollHeight = 1_300
+      resized()
+      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 800 })
+      scrollTo(800, 1_300) // Deliver the pin's own scroll before the next reader movement.
+      // The first upward movement can arrive in resize before its scroll event.
+      pageScroller.input('wheel')
+      pageScroller.scrollTop = 780
+      resized()
+      expect(browserHolds()).toBe(true)
+      scrollTo(799, 1_300)
+      expect(browserHolds()).toBe(false)
+      now.mockRestore()
     })
 
-    it("opens another chat at its measured end, not the last chat's", async () => {
+    it('detaches a following reader who drags up slowly, one pixel per scroll event', async () => {
+      // iOS, where it happened: WebKit has no anchoring, so every move that isn't a clamp is the reader's.
+      vi.stubGlobal('navigator', {
+        userAgent:
+          'Mozilla/5.0 (iPhone) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Safari/604.1'
+      })
+      await render({ folded: ['a1', 'a2', 'a3'].map((id) => assistantTurn(id, id)) })
+      scrollTo(500, 1_000)
+      resized()
+      const pins = scrollToOffset.mock.calls.length
+      // Each step's frame reconciles what it drew, as the browser's resize step does.
+      for (let top = 499; top >= 470; top -= 1) {
+        scrollTo(top, 1_000)
+        resized()
+      }
+      // A reply lands: the reader who dragged 30px up is not pulled back to the end.
+      pageScroller.scrollHeight = 1_063
+      resized()
+      expect(scrollToOffset.mock.calls.length).toBe(pins)
+    })
+
+    it('resumes following after a slow one-pixel return to the end on Safari', async () => {
+      vi.stubGlobal('navigator', {
+        userAgent:
+          'Mozilla/5.0 (iPhone) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Safari/604.1'
+      })
+      await render({ folded: ['a1', 'a2', 'a3'].map((id) => assistantTurn(id, id)) })
+      scrollTo(500, 1_000)
+      resized()
+      // Deliver the initial pin's own scroll before the reader moves.
+      scrollTo(500, 1_000)
+      scrollTo(470, 1_000)
+      resized()
+      const pins = scrollToOffset.mock.calls.length
+
+      for (let top = 471; top <= 500; top += 1) {
+        scrollTo(top, 1_000)
+        resized()
+        expect(scrollToOffset.mock.calls.length).toBe(pins)
+      }
+
+      pageScroller.scrollHeight = 1_063
+      resized()
+      expect(scrollToOffset.mock.calls.length).toBe(pins + 1)
+      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 563 })
+      expect(pageScroller.scrollTop).toBe(563)
+    })
+
+    it.each([false, true])(
+      'leaves a parked reader parked when a collapse below them clamps the page onto its end (finger down: %s)',
+      async (fingerDown) => {
+        await render({ folded: ['a1', 'a2', 'a3'].map((id) => assistantTurn(id, id)) })
+        scrollTo(500, 1_000)
+        resized()
+        // Parked 29 px short of the end by the reader's own wheel.
+        pageScroller.input('wheel')
+        scrollTo(471, 1_000)
+        const pins = scrollToOffset.mock.calls.length
+
+        // A run below collapses: the browser clamps onto the shorter end, possibly under the tap.
+        if (fingerDown) {
+          pageScroller.input('touchstart')
+        }
+        scrollTo(200, 700)
+        resized()
+        if (fingerDown) {
+          pageScroller.input('touchend')
+        }
+        // A reply lands. Main leaves the reader where the clamp put them; so does the page.
+        pageScroller.scrollHeight = 763
+        resized()
+        expect(scrollToOffset.mock.calls.length).toBe(pins)
+      }
+    )
+
+    it("opens another chat at its live end, not the last chat's", async () => {
       await render({ folded: [assistantTurn('a1', 'Chat A')] })
-      act(() => list().props.onContentSizeChange(320, 1_000))
+      scrollTo(500, 1_000)
+      // The next chat is taller; its size report hasn't come yet.
       pageScroller.scrollHeight = 2_500
-      scrollToEnd.mockClear()
+      scrollToOffset.mockClear()
 
       await update({ folded: [assistantTurn('b1', 'Chat B')], sendSurfaceId: 'tab-b' })
 
       expect(scrollToEnd).not.toHaveBeenCalled()
-      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 2_500 })
+      expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 2_000 })
     })
 
-    it('pages in history when the reader scrolls up to the top, not when a pin passes it', async () => {
+    it('loads older history from the Load earlier control, not from reaching the top', async () => {
       const onLoadEarlier = vi.fn()
       await render({ folded: [assistantTurn('a1', 'Latest')], hasMore: true, onLoadEarlier })
 
-      act(() => list().props.onScroll(scrolledTo(40, 540)))
+      // Down to the top and into iOS's bounce past it.
+      act(() => {
+        page().props.onScroll(scrolledTo(40, 540))
+        page().props.onScroll(scrolledTo(-15, 540))
+      })
       expect(onLoadEarlier).not.toHaveBeenCalled()
 
-      act(() => list().props.onScroll(scrolledTo(10, 540)))
+      act(() => loadEarlier().props.onPress())
       expect(onLoadEarlier).toHaveBeenCalledOnce()
     })
   })
diff --git a/mobile/src/session/MobileNativeChatView.render-stubs.test-fixture.ts b/mobile/src/session/MobileNativeChatView.render-stubs.test-fixture.ts
index 6c4678fce86..484e9de916a 100644
--- a/mobile/src/session/MobileNativeChatView.render-stubs.test-fixture.ts
+++ b/mobile/src/session/MobileNativeChatView.render-stubs.test-fixture.ts
@@ -3,7 +3,29 @@ import { vi } from 'vitest'
 const scrollToEnd = vi.hoisted(() => vi.fn())
 const scrollToOffset = vi.hoisted(() => vi.fn())
 const platform = vi.hoisted(() => ({ OS: 'ios' }))
-const pageScroller = vi.hoisted(() => ({ scrollHeight: 0 }))
+// The page list's live DOM geometry.
+const pageScroller = vi.hoisted(() => {
+  const listeners = new Map<string, Set<(event?: unknown) => void>>()
+  return {
+    scrollTop: 0,
+    scrollHeight: 0,
+    clientHeight: 500,
+    clientWidth: 320,
+    style: { overflowAnchor: '' },
+    getInnerViewNode: () => ({}),
+    getBoundingClientRect: () => ({ top: 0, bottom: 500 }),
+    addEventListener: (type: string, listener: (event?: unknown) => void) => {
+      listeners.set(type, (listeners.get(type) ?? new Set()).add(listener))
+    },
+    removeEventListener: (type: string, listener: (event?: unknown) => void) => {
+      listeners.get(type)?.delete(listener)
+    },
+    // The browser's scroll event at the scroller's current position.
+    scroll: () => listeners.get('scroll')?.forEach((listener) => listener()),
+    // The reader's hand on the scroller, e.g. a wheel turn.
+    input: (type: string) => listeners.get(type)?.forEach((listener) => listener())
+  }
+})
 
 export async function reactNativeStub() {
   const React = await import('react')
@@ -16,6 +38,17 @@ export async function reactNativeStub() {
     }),
     Platform: platform,
     Pressable: 'Pressable',
+    // The page's list scrolls through it.
+    ScrollView: React.forwardRef((props, ref) => {
+      const handle = {
+        scrollTo: ({ y, animated }: { y: number; animated: boolean }) =>
+          scrollToOffset({ animated, offset: y }),
+        scrollToEnd,
+        getScrollableNode: () => pageScroller
+      }
+      React.useImperativeHandle(ref, () => handle, [])
+      return React.createElement('ScrollView', props)
+    }),
     StyleSheet: { create: (styles: unknown) => styles, hairlineWidth: 1 },
     Text: 'Text',
     View: 'View'
diff --git a/mobile/src/session/MobileNativeChatView.tail-follow.test.ts b/mobile/src/session/MobileNativeChatView.tail-follow.test.ts
index 8d78eed4f9a..5e454156777 100644
--- a/mobile/src/session/MobileNativeChatView.tail-follow.test.ts
+++ b/mobile/src/session/MobileNativeChatView.tail-follow.test.ts
@@ -6,6 +6,7 @@ import {
   list,
   pressSend,
   render,
+  renderedRow,
   root,
   scrollAwayFromTail,
   scrollToEnd,
@@ -335,6 +336,21 @@ describe('MobileNativeChatView: tail-follow', () => {
     expect(control('Collapse tool runs')).toHaveLength(1)
   })
 
+  it('starts an initially empty switched-to native chat following, preserving Tools', async () => {
+    const toolTurn = (id: string): ReturnType<typeof assistantTurn> => ({
+      ...assistantTurn(id, ''),
+      blocks: [{ type: 'tool-call', name: 'Bash', callId: id, input: { command: 'ls' } }]
+    })
+    await render({ folded: [toolTurn('a')] })
+    act(() => root().findAllByProps({ accessibilityLabel: 'Expand tool runs' })[0].props.onPress())
+    await scrollAwayFromTail()
+    await update({ sendSurfaceId: 'tab-b', folded: [] })
+    await update({ sendSurfaceId: 'tab-b', folded: [toolTurn('b')] })
+    act(() => list().props.onContentSizeChange(320, 1300))
+    expect(scrollToOffset).toHaveBeenLastCalledWith({ animated: false, offset: 1300 })
+    expect(renderedRow('b').props.toolsExpanded).toBe(true)
+  })
+
   it('repins after a keyboard-driven viewport layout only while following', async () => {
     vi.useFakeTimers()
     try {
diff --git a/mobile/src/session/MobileNativeChatView.tsx b/mobile/src/session/MobileNativeChatView.tsx
index 4a811e92b64..39fb68ec1c3 100644
--- a/mobile/src/session/MobileNativeChatView.tsx
+++ b/mobile/src/session/MobileNativeChatView.tsx
@@ -6,7 +6,6 @@ import {
 } from './mobile-native-chat-disclosure-store'
 import {
   ActivityIndicator,
-  FlatList,
   type NativeScrollEvent,
   type NativeSyntheticEvent,
   Text,
@@ -31,12 +30,9 @@ import {
   mobileNativeChatEmptyState,
   type MobileNativeChatPendingItem
 } from './mobile-native-chat-render-data'
-import { useMobileNativeChatPageHistory } from './use-mobile-native-chat-page-history'
+import { useMobileNativeChatRowKeys } from './mobile-native-chat-row-keys'
 import { useMobileNativeChatPinchGesture } from './use-mobile-native-chat-pinch-gesture'
-import {
-  mobileNativeChatRowAnchor,
-  useMobileNativeChatTailFollow
-} from './use-mobile-native-chat-tail-follow'
+import { useMobileNativeChatTailFollow } from './use-mobile-native-chat-tail-follow'
 import { useMobileNativeChatTurnDisclosure } from './use-mobile-native-chat-turn-disclosure'
 import {
   mobileNativeChatComposerPlaceholder,
@@ -56,8 +52,10 @@ import type { MobileChatPermission } from './mobile-native-chat-permission'
 import type { MobileChatQuestion } from './mobile-native-chat-question'
 import type { MobileNativeChatSessionOptionPickersProps } from './MobileNativeChatSessionOptionPickers'
 import { MobileNativeChatScrollHold } from './MobileNativeChatScrollHold'
+import { MobileNativeChatRowList } from './MobileNativeChatRowList'
 import { useMobileNativeChatRowRenderer } from './use-mobile-native-chat-row-renderer'
 import type { MobileNativeChatStatus } from './use-mobile-native-chat-session'
+import type { OlderPagePhase } from './use-mobile-older-page-loader'
 
 /** Why the composer input is locked: the transport is disconnected, or the
  *  terminal subscription has not acknowledged its input lease yet. */
@@ -94,8 +92,9 @@ type Props = ComposerTrayProps & {
    *  by the overlay against the transcript catching up. */
   streaming: string | null
   hasMore?: boolean
-  loadingEarlier?: boolean
-  onLoadEarlier?: () => void
+  olderPages?: OlderPagePhase
+  /** `settled`: on the page, an older page waits for it so it never lands under a moving reader. */
+  onLoadEarlier?: (settled?: () => Promise<void>) => void
   onSend: (text: string) => Promise<boolean>
   /** Route identity used to fence accepted sends that settle after a tab/view switch. */
   sendSurfaceId: string
@@ -185,7 +184,7 @@ export function MobileNativeChatView({
   onStop,
   streaming,
   hasMore,
-  loadingEarlier,
+  olderPages = 'idle',
   onLoadEarlier,
   onSend,
   sendSurfaceId,
@@ -250,19 +249,8 @@ export function MobileNativeChatView({
       }),
     [messages, folded, streaming, pending, imagePreviewsByMessageId]
   )
-  const {
-    listRef,
-    showJumpToTail,
-    pinToTail,
-    pinToTailAfterContentResize,
-    jumpToTail,
-    beginUserScroll,
-    endUserDrag,
-    beginMomentum,
-    endMomentum,
-    readerIsScrolling,
-    recordScrollMetrics
-  } = useMobileNativeChatTailFollow({ items: data, scopeKey: sendSurfaceId })
+  const tail = useMobileNativeChatTailFollow({ hasItems: data.length > 0, scopeKey: sendSurfaceId })
+  const { jumpToTail, recordScrollMetrics, scrollMayLoadEarlier, pageSettled } = tail
 
   const handleSend = useCallback(
     async (text: string): Promise<boolean> => {
@@ -280,18 +268,19 @@ export function MobileNativeChatView({
     [onSend, onClearSendError, jumpToTail]
   )
 
-  const loadEarlier = useCallback(() => onLoadEarlier?.(), [onLoadEarlier])
+  const loadEarlier = useCallback(() => onLoadEarlier?.(pageSettled), [onLoadEarlier, pageSettled])
 
   const onScroll = useCallback(
     (e: NativeSyntheticEvent<NativeScrollEvent>) => {
       const { contentOffset } = e.nativeEvent
       recordScrollMetrics(e.nativeEvent)
-      // Near the top — page in older history. Only the reader's scroll: a pin reports offsets too.
-      if (contentOffset.y < 60 && hasMore && !loadingEarlier && readerIsScrolling()) {
+      // Near the top — page in older history. Only the reader's drag: a pin reports offsets too.
+      // After a failure only a tap retries, so a reader still at the top can't loop the spinner.
+      if (contentOffset.y < 60 && hasMore && olderPages === 'idle' && scrollMayLoadEarlier()) {
         loadEarlier()
       }
     },
-    [hasMore, loadingEarlier, loadEarlier, readerIsScrolling, recordScrollMetrics]
+    [hasMore, olderPages, loadEarlier, scrollMayLoadEarlier, recordScrollMetrics]
   )
 
   // Per-turn status rows: one live indicator while the turn runs, then a settled
@@ -312,10 +301,13 @@ export function MobileNativeChatView({
     scopeKey: sendSurfaceId
   })
 
-  // What the reader opened in this chat's runs, kept above the rows the list recycles.
+  // What the reader opened in this chat's runs, kept above the rows the list recycles or windows out.
+  const rowKeys = useMobileNativeChatRowKeys(folded, messages, sendSurfaceId, turns.presentation)
   const disclosures = useMobileNativeChatDisclosures(sendSurfaceId)
   const taskListPredecessors = useMemo(() => nativeChatTaskListPredecessors(data), [data])
   const renderItem = useMobileNativeChatRowRenderer({
+    rowKeyOf: rowKeys.keyOf,
+    runOwners: rowKeys.runOwners,
     toolsExpanded,
     taskListPredecessors,
     fontScale,
@@ -328,8 +320,6 @@ export function MobileNativeChatView({
     actionablePromptIds
   })
 
-  const history = useMobileNativeChatPageHistory(turns.listMessages, renderItem, sendSurfaceId)
-
   const liveStatus = turns.liveLine ? (
     <MobileNativeChatLiveLine
       line={turns.liveLine}
@@ -340,7 +330,15 @@ export function MobileNativeChatView({
   ) : null
   const toolCallCount = useMemo(() => mobileNativeChatToolCallCount(folded), [folded])
   const toggleTools = useCallback(() => setToolsExpanded((v) => !v), [])
+  const listContentStyle =
+    toolCallCount > 0 ? styles.listContentUnderFloatingControls : styles.listContent
 
+  const header = mobileNativeChatListHeader(hasMore, olderPages, loadEarlier)
+  // How rows draw: a change re-lays every row, which the place-hold and the window both follow.
+  const layoutKey = `${fontScale}:${toolsExpanded}`
+  const pageHeader = (measuring: boolean) =>
+    mobileNativeChatListHeader(hasMore, olderPages, loadEarlier, measuring)
+  const footer = mobileNativeChatListFooter(liveStatus, turns.waitingRows, renderItem)
   const emptyState = mobileNativeChatEmptyState(status, agent ?? null, error)
 
   const lockReason = useSettledMobileNativeChatInputLock(inputLockReason)
@@ -370,45 +368,30 @@ export function MobileNativeChatView({
       ) : (
         <GestureHandlerRootView style={styles.listWrap}>
           <MobileNativeChatDisclosureContext.Provider value={disclosures}>
-            <MobileNativeChatScrollHold headKey={turns.listMessages[0]?.id} listRef={listRef} />
-            <GestureDetector gesture={pinchGesture}>
-              <FlatList
-                ref={listRef}
-                data={history.listRows}
-                keyExtractor={(item) => item.id}
-                renderItem={history.renderListRow}
-                contentContainerStyle={
-                  toolCallCount > 0 ? styles.listContentUnderFloatingControls : styles.listContent
-                }
-                // Let link/file taps land while the composer keyboard is up
-                // instead of being swallowed by the dismiss gesture.
-                keyboardShouldPersistTaps="handled"
-                onScroll={onScroll}
-                onScrollBeginDrag={beginUserScroll}
-                onScrollEndDrag={endUserDrag}
-                onMomentumScrollBegin={beginMomentum}
-                onMomentumScrollEnd={endMomentum}
-                scrollEventThrottle={32}
-                onContentSizeChange={pinToTailAfterContentResize}
-                onLayout={pinToTail}
-                maintainVisibleContentPosition={mobileNativeChatRowAnchor(hasMore === true)}
-                ListHeaderComponent={history.withHistory(
-                  mobileNativeChatListHeader(hasMore, loadingEarlier, loadEarlier)
-                )}
-                ListFooterComponent={mobileNativeChatListFooter(
-                  liveStatus,
-                  turns.waitingRows,
-                  renderItem
-                )}
-                ListEmptyComponent={emptyStateView}
-              />
-            </GestureDetector>
+            <MobileNativeChatScrollHold
+              {...{ rowKeys, layoutKey, ...tail.placeHold }}
+              roots={disclosures.roots}
+              runPlacements={rowKeys.runPlacements}
+            >
+              <GestureDetector gesture={pinchGesture}>
+                <MobileNativeChatRowList
+                  {...{ tail, rowKeys, renderItem, footer, emptyStateView, onScroll, layoutKey }}
+                  rows={turns.listMessages}
+                  roots={disclosures.roots}
+                  rowState={turns.resolveRow}
+                  contentContainerStyle={listContentStyle}
+                  header={pageHeader}
+                  nativeHeader={header}
+                  hasHeader={hasMore === true}
+                />
+              </GestureDetector>
+            </MobileNativeChatScrollHold>
           </MobileNativeChatDisclosureContext.Provider>
           <MobileNativeChatFloatingControls
             toolCallCount={toolCallCount}
             toolsExpanded={toolsExpanded}
             onToggleTools={toggleTools}
-            showJumpToTail={showJumpToTail}
+            showJumpToTail={tail.showJumpToTail}
             onJumpToTail={jumpToTail}
           />
         </GestureHandlerRootView>
diff --git a/mobile/src/session/mobile-native-chat-disclosure-store.ts b/mobile/src/session/mobile-native-chat-disclosure-store.ts
index d84f4e62f36..cc07f777dce 100644
--- a/mobile/src/session/mobile-native-chat-disclosure-store.ts
+++ b/mobile/src/session/mobile-native-chat-disclosure-store.ts
@@ -2,10 +2,14 @@
 // disclosures live when the row itself may be unmounted: a run or line the reader opened
 // stays open after the list recycles its row, on reload, and across the Tools toggle.
 
-import { createContext, useCallback, useContext, useMemo, useState } from 'react'
+import { createContext, useCallback, useContext, useLayoutEffect, useMemo, useState } from 'react'
+import {
+  MobileNativeChatScrollRoots,
+  type MobileNativeChatRootPosition
+} from './mobile-native-chat-scroll-roots'
 
 /** Where the reader left an opened run's own scroll box. */
-export type MobileNativeChatRunScroll = { top: number; followsEnd: boolean }
+export type MobileNativeChatRunScroll = MobileNativeChatRootPosition
 
 export type MobileNativeChatDisclosureStore = {
   read: (key: string) => boolean | undefined
@@ -13,6 +17,7 @@ export type MobileNativeChatDisclosureStore = {
   /** By the run's disclosure key, and forgotten when that run closes. A plain map, not state:
    *  scrolling a run must not re-render the transcript. */
   runScroll: Map<string, MobileNativeChatRunScroll>
+  roots: MobileNativeChatScrollRoots
 }
 
 export const MobileNativeChatDisclosureContext =
@@ -25,10 +30,17 @@ type ScopedDisclosures = {
   scopeKey: string
   open: ReadonlyMap<string, boolean>
   runScroll: Map<string, MobileNativeChatRunScroll>
+  roots: MobileNativeChatScrollRoots
 }
 
 function emptyDisclosures(scopeKey: string): ScopedDisclosures {
-  return { scopeKey, open: new Map(), runScroll: new Map() }
+  const runScroll = new Map<string, MobileNativeChatRunScroll>()
+  return {
+    scopeKey,
+    open: new Map(),
+    runScroll,
+    roots: new MobileNativeChatScrollRoots(runScroll, MAX_DISCLOSURES)
+  }
 }
 
 /** One store per chat: another chat's choices never leak in. */
@@ -37,12 +49,13 @@ export function useMobileNativeChatDisclosures(scopeKey: string): MobileNativeCh
   if (state.scopeKey !== scopeKey) {
     setState(emptyDisclosures(scopeKey))
   }
-  const { open, runScroll } = state
+  const { open, runScroll, roots } = state
+  useLayoutEffect(() => () => roots.dispose(), [roots])
   const write = useCallback(
     (key: string, next: boolean) => {
       // Forgotten with the run that closed, as desktop does.
       if (!next) {
-        runScroll.delete(key)
+        roots.forget(key)
       }
       setState((current) => {
         if (current.open.get(key) === next) {
@@ -60,11 +73,11 @@ export function useMobileNativeChatDisclosures(scopeKey: string): MobileNativeCh
         return { ...current, open: updated }
       })
     },
-    [runScroll]
+    [roots]
   )
   return useMemo(
-    () => ({ read: (key: string) => open.get(key), write, runScroll }),
-    [open, write, runScroll]
+    () => ({ read: (key: string) => open.get(key), write, runScroll, roots }),
+    [open, write, runScroll, roots]
   )
 }
 
diff --git a/mobile/src/session/mobile-native-chat-fold-reuse.ts b/mobile/src/session/mobile-native-chat-fold-reuse.ts
new file mode 100644
index 00000000000..53524cd97a9
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-fold-reuse.ts
@@ -0,0 +1,46 @@
+import { useLayoutEffect, useMemo, useRef } from 'react'
+import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
+
+/** The fold rebuilt this row with nothing in it changed: the same fields and the same block objects
+ *  in the same order. Its id only names the candidate; content decides. */
+function unchanged(previous: NativeChatMessage, next: NativeChatMessage): boolean {
+  if (
+    previous.blocks.length !== next.blocks.length ||
+    previous.blocks.some((block, at) => block !== next.blocks[at])
+  ) {
+    return false
+  }
+  const fields = new Map(Object.entries(previous))
+  const nextFields = Object.entries(next)
+  return (
+    fields.size === nextFields.length &&
+    nextFields.every(([name, value]) => name === 'blocks' || fields.get(name) === value)
+  )
+}
+
+/** The folded rows, keeping each unchanged row's last committed object: a raw message re-folds the
+ *  whole window, which copies every tool run, so rows that drew nothing new would draw again. Only
+ *  the last committed rows of the chat shown are kept. */
+export function useMobileNativeChatFoldReuse(
+  folded: NativeChatMessage[],
+  scope: string
+): NativeChatMessage[] {
+  const committed = useRef<{ scope: string; byId: Map<string, NativeChatMessage> } | null>(null)
+  const rows = useMemo(() => {
+    const byId = committed.current?.scope === scope ? committed.current.byId : null
+    let kept = 0
+    const out = folded.map((row) => {
+      const previous = byId?.get(row.id)
+      if (previous && previous !== row && unchanged(previous, row)) {
+        kept += 1
+        return previous
+      }
+      return row
+    })
+    return kept > 0 ? out : folded
+  }, [folded, scope])
+  useLayoutEffect(() => {
+    committed.current = { scope, byId: new Map(rows.map((row) => [row.id, row])) }
+  }, [rows, scope])
+  return rows
+}
diff --git a/mobile/src/session/mobile-native-chat-list-header.tsx b/mobile/src/session/mobile-native-chat-list-header.tsx
index bb3e61c374f..30c9a0387a3 100644
--- a/mobile/src/session/mobile-native-chat-list-header.tsx
+++ b/mobile/src/session/mobile-native-chat-list-header.tsx
@@ -1,17 +1,32 @@
 import type { ReactElement } from 'react'
-import { ActivityIndicator, Pressable, Text } from 'react-native'
+import { ActivityIndicator, Pressable, Text, View } from 'react-native'
 import { colors } from '../theme/mobile-theme'
 import { styles } from './mobile-native-chat-view-styles'
+import type { OlderPagePhase } from './use-mobile-older-page-loader'
 
-/** The "Load earlier messages" control, while older history remains. */
+const LOAD_EARLIER_FAILED = "Couldn't load earlier messages. Tap to try again."
+const EARLIER_UNAVAILABLE = "Earlier messages can't be loaded."
+
+/** The "Load earlier messages" control, while older history remains. `measuring`: the page has loaded
+ *  rows above it still to draw, so it shows loading until they are in. */
 export function mobileNativeChatListHeader(
   hasMore: boolean | undefined,
-  loadingEarlier: boolean | undefined,
-  loadEarlier: () => void
+  olderPages: OlderPagePhase | undefined,
+  loadEarlier: () => void,
+  measuring = false
 ): ReactElement | null {
-  if (!hasMore) {
+  if (olderPages === 'unavailable' && !measuring) {
+    // No retry gets past it, so the control gives way to a line that says so.
+    return (
+      <View style={styles.loadEarlier}>
+        <Text style={styles.loadEarlierFailedText}>{EARLIER_UNAVAILABLE}</Text>
+      </View>
+    )
+  }
+  if (!hasMore && !measuring) {
     return null
   }
+  const loadingEarlier = measuring || olderPages === 'loading'
   return (
     <Pressable style={styles.loadEarlier} onPress={loadEarlier} disabled={loadingEarlier}>
       {loadingEarlier ? (
@@ -19,6 +34,9 @@ export function mobileNativeChatListHeader(
       ) : (
         <Text style={styles.loadEarlierText}>Load earlier messages</Text>
       )}
+      {olderPages === 'failed' ? (
+        <Text style={styles.loadEarlierFailedText}>{LOAD_EARLIER_FAILED}</Text>
+      ) : null}
     </Pressable>
   )
 }
diff --git a/mobile/src/session/mobile-native-chat-page-anchoring.ts b/mobile/src/session/mobile-native-chat-page-anchoring.ts
new file mode 100644
index 00000000000..5247ab7e01c
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-page-anchoring.ts
@@ -0,0 +1,67 @@
+import { scrollWritesStopMomentum } from './mobile-native-chat-page-motion'
+
+type Styled = {
+  style?: { overflowAnchor: string }
+  scrollTop: number
+  getBoundingClientRect: () => unknown
+}
+
+/** Who keeps a parked reader's place where the browser has scroll anchoring (not WebKit): the
+ *  browser, which sees every change inside the rows on screen, except while the page owns the
+ *  scroll: following (its end pin) or a place-hold's own correction. Two owners would each put the
+ *  same move back. */
+export class MobileNativeChatPageAnchoring {
+  private holds = 0
+  private readonly none = scrollWritesStopMomentum()
+
+  constructor(
+    private readonly scroller: () => Styled | null | undefined,
+    private readonly following: () => boolean
+  ) {}
+
+  /** The page takes the scroll for one correction, or gives it back. */
+  hold(on: boolean): void {
+    this.holds = Math.max(0, this.holds + (on ? 1 : -1))
+    this.sync()
+  }
+
+  sync(): void {
+    const s = this.scroller()
+    const next = this.holds === 0 && !this.following() ? 'auto' : 'none'
+    if (this.none || !s?.style || s.style.overflowAnchor === next) {
+      return
+    }
+    // Laid out under the old owner first, and the new one in force before anything changes.
+    s.getBoundingClientRect()
+    s.style.overflowAnchor = next
+    s.getBoundingClientRect()
+    if (next === 'auto') {
+      // Not one kept from before the page's turn, whose move the browser would then put back too.
+      this.rechoose(s)
+    }
+  }
+
+  /** After each commit. While the browser holds the place, rows new on screen can't be its anchor
+   *  until laid out, so it kept the container around them, whose top never moves. Laid out now, a
+   *  scroll makes it choose among them. */
+  committed(): void {
+    this.sync()
+    const s = this.scroller()
+    if (this.none || this.holds > 0 || s?.style?.overflowAnchor !== 'auto') {
+      return
+    }
+    s.getBoundingClientRect()
+    this.rechoose(s)
+  }
+
+  /** A scroll makes the browser choose its anchor afresh; at the very top it keeps none anyway. It
+   *  ends where it started, so the scroll event after it reports only what else moved the scroll;
+   *  taken as the page's own writes, a reader's scroll landing there would be too. */
+  private rechoose(s: Styled): void {
+    const top = s.scrollTop
+    if (top >= 0.5) {
+      s.scrollTop = top - 1
+      s.scrollTop = top
+    }
+  }
+}
diff --git a/mobile/src/session/mobile-native-chat-page-heights.test.ts b/mobile/src/session/mobile-native-chat-page-heights.test.ts
new file mode 100644
index 00000000000..2b17925019b
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-page-heights.test.ts
@@ -0,0 +1,40 @@
+import { expect, it } from 'vitest'
+import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
+import { MobileNativeChatPageHeights } from './mobile-native-chat-page-heights'
+import type { MobileNativeChatTurnRow } from './use-mobile-native-chat-turn-disclosure'
+
+it('retires replaced source payloads without changing spacers or sweeping same-key content updates', () => {
+  const cache = new MobileNativeChatPageHeights()
+  const row = (id: string): NativeChatMessage => ({
+    id,
+    role: 'user',
+    blocks: [],
+    source: 'transcript',
+    timestamp: 1
+  })
+  const keyOf = (m: NativeChatMessage) => m.id
+  const state: MobileNativeChatTurnRow = {
+    turnStatus: null,
+    turnExpanded: false,
+    activeTurnIsWorking: false,
+    trailingRun: false,
+    mayStillGrow: false,
+    reasoningExpanded: false,
+    onToggleReasoning: () => {},
+    onToggleSubagentGroup: () => {},
+    reasoningIsLive: false,
+    userMessageOpen: false,
+    onToggleUserMessage: () => {}
+  }
+  cache.remember('head', 80, row('head'), state, 'layout')
+  cache.remember('retired', 20, row('retired'), state, 'layout')
+  const before = ['head', 'retired', 'unknown']
+  const source = cache.sourceKeys(['head', 'replacement', 'unknown'].map(row), keyOf, before)
+  expect(source.changed).toBe(true)
+  const slack = cache.px('retired')!
+  const geometry = cache.spacers(source.keys, [0, 0], [0, 1], slack)
+  cache.retain(source.keys)
+  expect(cache.px('retired')).toBeUndefined()
+  expect(cache.spacers(source.keys, [0, 0], [0, 1], slack)).toEqual(geometry)
+  expect(cache.sourceKeys(source.keys.map(row), keyOf, source.keys).changed).toBe(false)
+})
diff --git a/mobile/src/session/mobile-native-chat-page-heights.ts b/mobile/src/session/mobile-native-chat-page-heights.ts
new file mode 100644
index 00000000000..d1292c0741d
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-page-heights.ts
@@ -0,0 +1,174 @@
+import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
+import type { MobileNativeChatTurnRow } from './use-mobile-native-chat-turn-disclosure'
+
+const FIRST_ESTIMATE = 80
+
+/** The drawn rows, as the measuring choice reads them. */
+type DrawnRows = {
+  keys: readonly string[]
+  rows: readonly NativeChatMessage[]
+  rowState: (index: number, row: NativeChatMessage) => MobileNativeChatTurnRow
+  start: number
+  /** The first row in the document: rows above it were never measured. */
+  first: number
+  following: boolean
+}
+
+type Entry = { px: number; row: NativeChatMessage; state: MobileNativeChatTurnRow; layout: string }
+
+function sameState(a: MobileNativeChatTurnRow, b: MobileNativeChatTurnRow): boolean {
+  const before = Object.entries(a)
+  const after = new Map(Object.entries(b))
+  return before.length === after.size && before.every(([name, value]) => after.get(name) === value)
+}
+
+/** Row heights as drawn. One holds while the row would draw the same: the same row object (unchanged
+ *  rows keep theirs across a re-fold), the same row state and the same layout. A stale one keeps
+ *  standing in for its row until it is measured again, so going stale never moves anything. */
+export class MobileNativeChatPageHeights {
+  private entries = new Map<string, Entry>()
+  private sum = 0
+  private samples = 0
+
+  px(key: string | undefined): number | undefined {
+    return key === undefined ? undefined : this.entries.get(key)?.px
+  }
+
+  /** For rows never drawn, which only ever sit below the reader. */
+  estimate(): number {
+    return this.samples > 0 ? this.sum / this.samples : FIRST_ESTIMATE
+  }
+
+  valid(
+    key: string,
+    row: NativeChatMessage,
+    state: MobileNativeChatTurnRow,
+    layout: string
+  ): boolean {
+    const entry = this.entries.get(key)
+    return (
+      entry !== undefined &&
+      entry.row === row &&
+      entry.layout === layout &&
+      sameState(entry.state, state)
+    )
+  }
+
+  remember(
+    key: string,
+    px: number,
+    row: NativeChatMessage,
+    state: MobileNativeChatTurnRow,
+    layout: string
+  ): void {
+    if (!this.entries.has(key)) {
+      this.samples += 1
+    }
+    this.sum += px - (this.entries.get(key)?.px ?? 0)
+    this.entries.set(key, { px, row, state, layout })
+  }
+
+  sourceKeys(
+    rows: readonly NativeChatMessage[],
+    keyOf: (row: NativeChatMessage) => string,
+    before: readonly string[] | undefined
+  ): {
+    keys: string[]
+    changed: boolean
+    indexOf: (key: string | undefined) => number | undefined
+  } {
+    let changed = before?.length !== rows.length
+    const keys = rows.map((row, index) => {
+      const key = keyOf(row)
+      changed ||= before?.[index] !== key
+      return key
+    })
+    let index: Map<string, number> | undefined
+    const indexOf = (key: string | undefined) =>
+      key === undefined ? undefined : (index ??= new Map(keys.map((k, at) => [k, at]))).get(key)
+    return { keys, changed, indexOf }
+  }
+
+  /** Retired payloads die after their heights supplied trim slack; estimation stays numeric. */
+  retain(keys: readonly string[]): void {
+    const current = new Set(keys)
+    for (const key of this.entries.keys()) {
+      if (!current.has(key)) {
+        this.entries.delete(key)
+      }
+    }
+  }
+
+  /** Spacer heights around the measuring rows `[m0, m1)` and the window `[start, end)`: above them
+   *  only the measured run (from `first`, plus trim `slack`), between them, and below the window. */
+  spacers(
+    keys: readonly string[],
+    [m0, m1]: [number, number],
+    [start, end]: [number, number],
+    slack: number
+  ): { first: number; above: number; mid: number; bottom: number } {
+    let [first, above, mid, bottom] = [m0, slack, 0, 0]
+    for (let px = this.px(keys[first - 1]); first > 0 && px !== undefined;) {
+      above += px
+      first -= 1
+      px = this.px(keys[first - 1])
+    }
+    for (let i = m1; i < start; i += 1) {
+      mid += this.px(keys[i]) ?? 0
+    }
+    for (let i = end; i < keys.length; i += 1) {
+      bottom += this.px(keys[i]) ?? this.estimate()
+    }
+    return { first, above, mid, bottom }
+  }
+
+  /** The run of rows nearest above `start` whose heights don't hold, `[from, to]`, at most `rows`
+   *  long and within `reach` px of measured rows above the window; null when there is none. */
+  nearestStale(
+    drawn: Pick<DrawnRows, 'keys' | 'rows' | 'rowState' | 'start'>,
+    layout: string,
+    reach: number,
+    rows: number
+  ): [number, number] | null {
+    const { keys, start } = drawn
+    const valid = (i: number): boolean =>
+      this.valid(keys[i]!, drawn.rows[i]!, drawn.rowState(i, drawn.rows[i]!), layout)
+    let [to, distance] = [start - 1, 0]
+    for (; to >= 0 && distance <= reach && valid(to); to -= 1) {
+      distance += this.px(keys[to]) ?? 0
+    }
+    if (to < 0 || distance > reach) {
+      return null
+    }
+    let from = to
+    while (from > 0 && to - from + 1 < rows && !valid(from - 1)) {
+      from -= 1
+    }
+    return [from, to]
+  }
+
+  /** The rows to measure next: stale ones within `near` px above the window; following, then the
+   *  rows never drawn just above the measured run; then, with `full`, stale ones anywhere above. */
+  next(
+    drawn: DrawnRows,
+    layout: string,
+    near: number,
+    rows: number,
+    full: boolean
+  ): [number, number] | null {
+    const close = this.nearestStale(drawn, layout, near, rows)
+    if (close || !drawn.following) {
+      return close
+    }
+    if (drawn.first > 0) {
+      return [Math.max(0, drawn.first - rows), drawn.first - 1]
+    }
+    return full ? this.nearestStale(drawn, layout, Infinity, rows) : null
+  }
+
+  clear(): void {
+    this.entries.clear()
+    this.sum = 0
+    this.samples = 0
+  }
+}
diff --git a/mobile/src/session/mobile-native-chat-page-motion.ts b/mobile/src/session/mobile-native-chat-page-motion.ts
new file mode 100644
index 00000000000..3c34a05ee61
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-page-motion.ts
@@ -0,0 +1,295 @@
+/** No touch and no scroll of the reader's for this long: a write any sooner can stop iOS momentum. */
+const REST_MS = 150
+/** Input this recent makes a move the reader's where the browser also moves the scroll. */
+const INTENT_MS = 1_000
+const SCROLL_KEYS = new Set(['ArrowDown', 'ArrowUp', 'End', 'Home', 'PageDown', 'PageUp', ' '])
+type Moved = { by: 'own' | 'layout' | 'reader' | 'none'; moved: number }
+export type MobileNativeChatPageObservation = Moved & { fromEnd: number }
+
+/** WebKit (every iOS browser, and Safari) stops a fling on any scroll write and has no scroll
+ *  anchoring; other engines keep momentum, and their anchoring keeps a parked reader's place. */
+export function scrollWritesStopMomentum(): boolean {
+  const agent = globalThis.navigator?.userAgent ?? ''
+  return /AppleWebKit/.test(agent) && !/Chrome|Chromium|Android/.test(agent)
+}
+
+/** Whether the page keeps a parked place itself: on WebKit, which has no scroll anchoring, and at the
+ *  very top, where Chromium's anchoring never adjusts (rows measured above would push the reader). */
+export function pageKeepsPlace(scrollTop: number): boolean {
+  return scrollWritesStopMomentum() || scrollTop < 0.5
+}
+
+type Listener = (event: unknown) => void
+type Listened = {
+  addEventListener: (type: string, listener: Listener, options: { passive: true }) => void
+  removeEventListener: (type: string, listener: Listener) => void
+}
+
+/** Which way a scroll key the page scrolls by moves it (1 down, -1 up); 0 for any other key, or one
+ *  typed into the composer. */
+function keyWay(event: unknown): number {
+  if (typeof KeyboardEvent === 'undefined' || !(event instanceof KeyboardEvent)) {
+    return 0
+  }
+  const { key, shiftKey, target } = event
+  const typing =
+    typeof HTMLElement !== 'undefined' &&
+    target instanceof HTMLElement &&
+    (/^(INPUT|TEXTAREA|SELECT)$/.test(target.tagName) || target.isContentEditable)
+  if (typing || !SCROLL_KEYS.has(key)) {
+    return 0
+  }
+  return /Up|Home/.test(key) || (key === ' ' && shiftKey) ? -1 : 1
+}
+
+function wheelWay(event: unknown): number {
+  const deltaY = typeof event === 'object' && event !== null && 'deltaY' in event && event.deltaY
+  return typeof deltaY === 'number' ? Math.sign(deltaY) : 0
+}
+
+function touchY(event: unknown): number | undefined {
+  const touches = typeof event === 'object' && event !== null && 'touches' in event && event.touches
+  const first = touches && typeof touches === 'object' && 0 in touches ? touches[0] : undefined
+  const y = typeof first === 'object' && first !== null && 'clientY' in first && first.clientY
+  return typeof y === 'number' ? y : undefined
+}
+
+/** Whether the reader is moving the page, told apart from the page's own writes. Work that can move
+ *  rows above the reader (a landing, a measured row, a correction) waits until it settles. */
+export class MobileNativeChatPageMotion {
+  private touching = false
+  private pointing = false
+  private lastInput = 0
+  /** Which way the reader's last input moves the page: 1 down, -1 up, 0 unknown (the scrollbar). */
+  private way = 0
+  private lastTouchY: number | undefined
+  private lastReaderScroll = 0
+  /** The browser moves the scroll too (its anchoring), so only input makes a move the reader's. */
+  private readonly browserMoves = !scrollWritesStopMomentum()
+  /** Where the page last accounted for the scroll: its write, an observed scroll, a resize. */
+  private seen = 0
+  private seenMax = Infinity
+  /** A commit changed what is drawn and its resize callback hasn't run: a move now is layout's. */
+  private unreconciled = false
+  private drawn = ''
+  private layouts = 0
+  /** Where the page's own writes put the scroller, until their scroll event arrives. */
+  private own: number[] = []
+  private timer: ReturnType<typeof setTimeout> | undefined
+  private later: ReturnType<typeof setTimeout> | undefined
+  /** Owed work doesn't run again before this, so other work gets frames between its rounds. */
+  private quietUntil = 0
+  /** Classified before the follower sees geometry, including layout and the page's writes. */
+  onMotion: ((observation: MobileNativeChatPageObservation) => void) | null = null
+  private waiters: (() => void)[] = []
+
+  constructor(
+    private readonly onSettled: () => void,
+    initialTop = 0
+  ) {
+    this.seen = initialTop
+  }
+
+  /** Follows the reader's hand on the scroller (touch, wheel, scroll keys, the scrollbar); returns
+   *  the detach. */
+  attach(scroller: Listened, acceptsKey: (event: unknown) => boolean = () => true): () => void {
+    const input = (way: number) => {
+      ;[this.lastInput, this.way] = [Date.now(), way]
+    }
+    const key = (event: unknown) => {
+      const way = keyWay(event)
+      if (way !== 0 && acceptsKey(event)) {
+        input(way)
+      }
+    }
+    const move = (event: unknown) => {
+      const [from, y] = [this.lastTouchY, touchY(event)]
+      this.lastTouchY = y
+      // A finger moving up scrolls the page down.
+      input(from !== undefined && y !== undefined && y !== from ? Math.sign(from - y) : this.way)
+    }
+    const start = (event: unknown) => {
+      this.lastTouchY = touchY(event)
+      input(0)
+      this.touch(true)
+    }
+    // The scrollbar, which is the scroller's own; a press on a row inside is no scroll.
+    const point = (event: unknown) => {
+      if (
+        typeof event === 'object' &&
+        event !== null &&
+        'target' in event &&
+        event.target === scroller
+      ) {
+        this.pointing = true
+        this.way = 0
+      }
+    }
+    // Released, or moving with no button down: a pointerup lost after a scrollbar drag can't stick.
+    const up = (event: unknown) => {
+      if (!(typeof event === 'object' && event !== null && 'buttons' in event && event.buttons)) {
+        this.pointing = false
+      }
+    }
+    const listeners: [Listened, string, Listener][] = [
+      [scroller, 'touchstart', start],
+      [scroller, 'touchend', () => this.touch(false)],
+      [scroller, 'touchcancel', () => this.touch(false)],
+      [scroller, 'touchmove', move],
+      [scroller, 'wheel', (event) => input(wheelWay(event))],
+      [scroller, 'pointerdown', point]
+    ]
+    // A scrollbar drag can end, and a scroll key arrive, outside the scroller.
+    if ('addEventListener' in globalThis) {
+      listeners.push([globalThis, 'pointerup', up], [globalThis, 'pointercancel', up])
+      listeners.push([globalThis, 'pointermove', up], [globalThis, 'keydown', key])
+    }
+    listeners.forEach(([target, type, fn]) => target.addEventListener(type, fn, { passive: true }))
+    return () => listeners.forEach(([target, type, fn]) => target.removeEventListener(type, fn))
+  }
+
+  touch(down: boolean): void {
+    this.touching = down
+    this.lastInput = Date.now()
+    if (down) {
+      this.own = []
+      clearTimeout(this.timer)
+      this.timer = undefined
+    } else {
+      this.poke()
+    }
+  }
+
+  /** A commit drew `drawn`. When that changed, a move is layout's until its resize callback (or the
+   *  next frame, when nothing resized); scroll events run before that frame's resize callbacks. */
+  laidOut(drawn: string): void {
+    if (drawn === this.drawn) {
+      return
+    }
+    this.drawn = drawn
+    this.unreconciled = true
+    const token = ++this.layouts
+    globalThis.requestAnimationFrame?.(() => {
+      if (token === this.layouts) {
+        this.unreconciled = false
+      }
+    })
+  }
+
+  /** The resize callback reconciled layout: what moved the scroll since the page last accounted
+   *  for it is now told apart (a scroll event may not have reported it yet). */
+  reconciled(scrollTop: number, max: number): Moved {
+    this.unreconciled = false
+    return this.account(scrollTop, max)
+  }
+
+  /** What moved the scroll to `scrollTop` since the page last accounted for it, and by how much. The
+   *  page's write; layout while a commit is unreconciled or rows above the reading place moved
+   *  (`placeMoved`), left for the resize callback to tell apart; else as `account`. */
+  scrolled(scrollTop: number, max: number, placeMoved: () => boolean): Moved {
+    const moved = scrollTop - this.seen
+    const at = this.own.findIndex((target) => Math.abs(target - scrollTop) <= 1)
+    if (at !== -1) {
+      this.own.splice(0, at + 1)
+      ;[this.seen, this.seenMax] = [scrollTop, max]
+      return this.observed('own', moved, max - scrollTop)
+    }
+    if (Math.abs(moved) >= 0.5 && !this.touching && (this.unreconciled || placeMoved())) {
+      return this.observed('layout', moved, max - scrollTop)
+    }
+    return this.account(scrollTop, max)
+  }
+
+  /** A clamp onto a shorter end is layout's; any other move is the reader's (a finger makes it so),
+   *  except where the browser moves the scroll too: there only input (or the fling it started) does. */
+  private account(scrollTop: number, max: number): Moved {
+    const [from, fromMax, moved] = [this.seen, this.seenMax, scrollTop - this.seen]
+    ;[this.seen, this.seenMax] = [scrollTop, max]
+    if (Math.abs(moved) < 0.5) {
+      return this.observed('none', moved, max - scrollTop)
+    }
+    // Pulled back onto a shorter end from where the old one allowed; iOS bouncing past an end is not.
+    const clamped = Math.abs(scrollTop - max) < 0.5 && from > max + 0.5 && from <= fromMax + 0.5
+    if ((clamped && !this.touching) || (this.browserMoves && !this.intended(moved))) {
+      return this.observed('layout', moved, max - scrollTop)
+    }
+    this.lastReaderScroll = Date.now()
+    this.poke()
+    return this.observed('reader', moved, max - scrollTop)
+  }
+
+  private observed(by: Moved['by'], moved: number, fromEnd: number): Moved {
+    this.onMotion?.({ by, moved, fromEnd })
+    return { by, moved }
+  }
+
+  /** Input is recent (a fling counts from the finger's release) and the move goes its way: the
+   *  browser's anchoring moving against it is the browser's, so it can't detach the reader. */
+  private intended(moved: number): boolean {
+    const recent = this.touching || this.pointing || Date.now() - this.lastInput <= INTENT_MS
+    return recent && (this.way === 0 || Math.sign(moved) === this.way)
+  }
+
+  wrote(target: number): void {
+    this.own = [...this.own.slice(-7), target]
+    this.seen = target
+  }
+
+  settled(): boolean {
+    return !this.touching && Date.now() - this.lastReaderScroll >= REST_MS
+  }
+
+  /** A place correction may be written now: at once where a write keeps momentum (as the common
+   *  list does), else only at rest. */
+  readonly mayCorrect = scrollWritesStopMomentum() ? () => this.settled() : () => true
+
+  /** Resolves once settled, or when the window goes away (`release`), so a wait never strands. */
+  whenSettled(): Promise<void> {
+    if (this.settled()) {
+      return Promise.resolve()
+    }
+    return new Promise((resolve) => {
+      this.waiters.push(resolve)
+      this.poke()
+    })
+  }
+
+  poke(): void {
+    if (this.touching || this.timer !== undefined) {
+      return
+    }
+    const now = Date.now()
+    const wait = Math.max(0, REST_MS - (now - this.lastReaderScroll), this.quietUntil - now)
+    this.timer = setTimeout(() => {
+      this.timer = undefined
+      if (!this.settled() || Date.now() < this.quietUntil) {
+        this.poke()
+        return
+      }
+      this.waiters.splice(0).forEach((resolve) => resolve())
+      this.onSettled()
+    }, wait)
+  }
+
+  /** Owed work waits `ms` before its next round. */
+  quiet(ms: number): void {
+    this.quietUntil = Date.now() + ms
+  }
+
+  /** Checks for owed work again after `ms`, when nothing else will. */
+  pokeIn(ms: number): void {
+    clearTimeout(this.later)
+    this.later = setTimeout(() => this.poke(), ms)
+  }
+
+  release(): void {
+    this.touching = false
+    this.pointing = false
+    this.lastReaderScroll = 0
+    this.own = []
+    clearTimeout(this.later)
+    clearTimeout(this.timer)
+    this.timer = undefined
+    this.waiters.splice(0).forEach((resolve) => resolve())
+  }
+}
diff --git a/mobile/src/session/mobile-native-chat-page-rows.ts b/mobile/src/session/mobile-native-chat-page-rows.ts
new file mode 100644
index 00000000000..98bbca6bb29
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-page-rows.ts
@@ -0,0 +1,118 @@
+type Scroller = { getBoundingClientRect: () => { top: number }; scrollTop: number }
+import { mobileNativeChatScrollFrame } from './mobile-native-chat-scroll-roots'
+
+function isElement(node: unknown): node is Element {
+  return typeof Element !== 'undefined' && node instanceof Element
+}
+
+/** The part of `row` at the screen's top line `view`: the first part starting on screen, or the
+ *  innermost one crossing the line, as the browser's own scroll anchoring would pick. Growth above
+ *  it inside the row then moves it, which the row's own top doesn't show. */
+function partAtTop(row: Element, view: number): Element {
+  let part = row
+  for (let child = row.firstElementChild; child;) {
+    const box = child.getBoundingClientRect()
+    if (box.bottom <= view || box.height === 0) {
+      child = child.nextElementSibling
+    } else if (mobileNativeChatScrollFrame(child, row) || box.top >= view) {
+      return child
+    } else {
+      part = child
+      child = child.firstElementChild
+    }
+  }
+  return part
+}
+
+/** The page's drawn row nodes by key, each in the one observer while drawn, and the row the reader
+ *  is reading: the first drawn row on screen and its offset from the scroller's top. */
+export class MobileNativeChatPageRows {
+  private nodes = new Map<string, Element>()
+  private keys = new WeakMap<Element, string>()
+  private refs = new Map<string, (node: unknown) => void>()
+  private observer: ResizeObserver | null = null
+  /** The row and the part of it at the screen's top; `top` from the scroller's top, with the
+   *  `scrollTop` it was read at. */
+  private anchor: { key: string; part: Element; top: number; scrollTop: number } | null = null
+
+  keyOf(node: Element): string | undefined {
+    return this.keys.get(node)
+  }
+
+  node(key: string | undefined): Element | undefined {
+    return key === undefined ? undefined : this.nodes.get(key)
+  }
+
+  readonly observeWith = (observer: ResizeObserver | null): void => {
+    this.observer = observer
+    this.nodes.forEach((node) => observer?.observe(node))
+  }
+
+  /** One ref per key for as long as the row is drawn, so a streamed commit never re-observes it. */
+  readonly ref = (key: string): ((node: unknown) => void) => {
+    let ref = this.refs.get(key)
+    if (!ref) {
+      ref = (node: unknown) => {
+        const was = this.nodes.get(key)
+        if (was) {
+          this.observer?.unobserve(was)
+          this.nodes.delete(key)
+        }
+        if (isElement(node)) {
+          this.nodes.set(key, node)
+          this.keys.set(node, key)
+          this.observer?.observe(node)
+        } else {
+          this.refs.delete(key)
+        }
+      }
+      this.refs.set(key, ref)
+    }
+    return ref
+  }
+
+  /** `deep`: anchor the part of the row at the screen's top, not the row's own top. */
+  takeAnchor(
+    scroller: Scroller,
+    keys: readonly string[],
+    [start, end]: [number, number],
+    deep: boolean
+  ): void {
+    const view = scroller.getBoundingClientRect().top
+    let [low, high] = [start, end]
+    while (low < high) {
+      const middle = low + Math.floor((high - low) / 2)
+      const node = this.node(keys[middle])
+      if (!node || node.getBoundingClientRect().bottom <= view) {
+        low = middle + 1
+      } else {
+        high = middle
+      }
+    }
+    const key = keys[low]
+    const node = this.node(key)
+    const part = node && (deep ? partAtTop(node, view) : node)
+    const top = part && part.getBoundingClientRect().top - view
+    this.anchor =
+      key && part && top !== undefined ? { key, part, top, scrollTop: scroller.scrollTop } : null
+  }
+
+  /** How far the anchored part moved in the content since it was taken (what is above it changed
+   *  size), apart from any scrolling; null when it isn't drawn. */
+  placeShift(scroller: Scroller): number | null {
+    const part = this.anchor?.part
+    if (!this.anchor || !part?.isConnected || !this.node(this.anchor.key)) {
+      return null
+    }
+    const now = part.getBoundingClientRect().top - scroller.getBoundingClientRect().top
+    return now + scroller.scrollTop - this.anchor.top - this.anchor.scrollTop
+  }
+
+  placeMoved(scroller: Scroller): boolean {
+    return Math.abs(this.placeShift(scroller) ?? 0) >= 0.5
+  }
+
+  forgetAnchor(): void {
+    this.anchor = null
+  }
+}
diff --git a/mobile/src/session/mobile-native-chat-page-window-coverage.ts b/mobile/src/session/mobile-native-chat-page-window-coverage.ts
new file mode 100644
index 00000000000..9f38a69c152
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-page-window-coverage.ts
@@ -0,0 +1,66 @@
+/** The drawn rows `[start, end)` of `n`, the first drawn row's top in content coordinates, and the
+ *  scroller's viewport. */
+export type MobileNativeChatWindowGeometry = {
+  n: number
+  start: number
+  end: number
+  following: boolean
+  windowTop: number
+  scrollTop: number
+  viewport: number
+}
+
+/** Rows within one screen of the viewport are drawn, rows past two are not; null when nothing
+ *  changes. Rows above the window come only from the spacer, which holds measured heights, so drawing
+ *  or dropping them never moves what the reader sees. `known` is a row's measured height. */
+export function coverMobileNativeChatWindow(
+  g: MobileNativeChatWindowGeometry,
+  known: (index: number) => number | undefined,
+  estimate: number
+): { start: number; end: number } | null {
+  const { n, following, scrollTop, viewport } = g
+  const height = (at: number): number => known(at) ?? estimate
+  const [near, far] = [scrollTop - viewport, scrollTop + 2 * viewport]
+  let [start, end, top] = [g.start, g.end, g.windowTop]
+  let bottom = top
+  for (let at = start; at < end; at += 1) {
+    bottom += height(at)
+  }
+  if (!following && (top > scrollTop + viewport || bottom < scrollTop)) {
+    // Nothing drawn is on screen, so nothing needs to stay still: draw where the reader is.
+    if (top > scrollTop) {
+      while (start > 0 && known(start - 1) !== undefined && top > scrollTop) {
+        start -= 1
+        top -= known(start)!
+      }
+    } else {
+      for (top = bottom, start = end; start < n - 1 && top + height(start) <= scrollTop;) {
+        top += height(start)
+        start += 1
+      }
+    }
+    start = Math.min(start, n - 1)
+    for (end = start, bottom = top; end < n && bottom < far; end += 1) {
+      bottom += height(end)
+    }
+  } else {
+    while (start > 0 && top > near && known(start - 1) !== undefined) {
+      start -= 1
+      top -= known(start)!
+    }
+    while (start < end - 1 && top + height(start) < scrollTop - 2 * viewport) {
+      top += height(start)
+      start += 1
+    }
+    while (end < n && bottom < far) {
+      bottom += height(end)
+      end += 1
+    }
+    while (!following && end - 1 > start && bottom - height(end - 1) > scrollTop + 3 * viewport) {
+      end -= 1
+      bottom -= height(end)
+    }
+  }
+  end = following ? n : Math.max(end, start + 1)
+  return start === g.start && end === g.end ? null : { start, end }
+}
diff --git a/mobile/src/session/mobile-native-chat-page-window-state.ts b/mobile/src/session/mobile-native-chat-page-window-state.ts
new file mode 100644
index 00000000000..95786058b18
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-page-window-state.ts
@@ -0,0 +1,66 @@
+import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
+import type { MobileNativeChatTurnRow } from './use-mobile-native-chat-turn-disclosure'
+import type { MobileNativeChatRowKeys } from './mobile-native-chat-row-keys'
+import type { MobileNativeChatScrollRoots } from './mobile-native-chat-scroll-roots'
+
+type Box = { top: number; bottom: number }
+type Measured = { getBoundingClientRect: () => Box }
+
+export type MobileNativeChatWindowScroller = Measured & {
+  scrollTop: number
+  scrollHeight: number
+  clientHeight: number
+  clientWidth: number
+  style?: { overflowAnchor: string }
+  addEventListener: (
+    type: string,
+    listener: (event: unknown) => void,
+    options: { passive: true }
+  ) => void
+  removeEventListener: (type: string, listener: (event: unknown) => void) => void
+}
+
+export type MobileNativeChatWindowRowState = (
+  index: number,
+  row: NativeChatMessage
+) => MobileNativeChatTurnRow
+export type MobileNativeChatWindowGroup = { from: string; fromAt: number; to: string; toAt: number }
+
+/** Where the window stands, by key, so landings and trims never change which rows are drawn. */
+export type MobileNativeChatWindowSeat = {
+  scope: string
+  first: string
+  firstAt: number
+  last: string | null
+  lastAt: number
+  /** Measured rows trimmed from above a parked reader: their height stays until settled. */
+  slack: number
+  /** Rows drawn in place above the window only so they get measured. */
+  measure: MobileNativeChatWindowGroup | null
+}
+
+export type MobileNativeChatWindowDrawn = {
+  keys: readonly string[]
+  rows: readonly NativeChatMessage[]
+  indexOf: (key: string | undefined) => number | undefined
+  rowState: MobileNativeChatWindowRowState
+  start: number
+  end: number
+  /** The first row in the document: rows above it were never measured. */
+  first: number
+  sourceHead: string | undefined
+  following: boolean
+  layoutKey: string
+}
+
+export type MobileNativeChatPageWindowArgs = {
+  roots?: MobileNativeChatScrollRoots
+  rows: readonly NativeChatMessage[]
+  rowKeys: Pick<MobileNativeChatRowKeys, 'scope' | 'sourceHead' | 'keyOf' | 'current'>
+  rowState: MobileNativeChatWindowRowState
+  following: boolean
+  /** At event time, before a re-render lands. */
+  isFollowing: () => boolean
+  layoutKey: string
+  scroller: () => MobileNativeChatWindowScroller | null | undefined
+}
diff --git a/mobile/src/session/mobile-native-chat-reading-place.test.tsx b/mobile/src/session/mobile-native-chat-reading-place.test.tsx
new file mode 100644
index 00000000000..26a37bb12a5
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-reading-place.test.tsx
@@ -0,0 +1,395 @@
+import { createElement as h, Fragment, useMemo, type ReactElement, type ReactNode } from 'react'
+import {
+  act,
+  create,
+  type ReactTestRenderer,
+  type ReactTestRendererJSON as Node
+} from 'react-test-renderer'
+import { expect, it, vi } from 'vitest'
+import { splitNativeChatBlocks } from '../../../src/shared/native-chat-tool-fold'
+import type { NativeChatBlock, NativeChatMessage } from '../../../src/shared/native-chat-types'
+import { foldMobileNativeChatMessages } from './mobile-native-chat-render-data'
+import {
+  useMobileNativeChatRowKeys,
+  type MobileNativeChatRowKeys
+} from './mobile-native-chat-row-keys'
+import { MobileNativeChatScrollHold, mobileNativeChatRowId } from './MobileNativeChatScrollHold'
+import { ToolRun } from './MobileNativeChatToolRun'
+
+const platform = vi.hoisted(() => ({ OS: 'web' }))
+// The page's own hold, as on iOS: where the browser has scroll anchoring it keeps these places
+// itself, and the hold runs only for a regroup or a move to another row.
+vi.stubGlobal('navigator', {
+  userAgent:
+    'Mozilla/5.0 (iPhone) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Safari/604.1'
+})
+
+vi.mock('react-native', async () => {
+  const React = await import('react')
+  // A class, so an opened run's box can scroll it the way it scrolls a real ScrollView.
+  class ScrollView extends React.Component<{ children?: ReactNode }> {
+    scrollToEnd = (): void => {}
+    scrollTo = (): void => {}
+    render(): ReactNode {
+      return React.createElement('div', null, this.props.children)
+    }
+  }
+  const settled = () => ({ start: (): void => {}, stop: (): void => {} })
+  return {
+    Platform: platform,
+    Text: 'span',
+    View: 'div',
+    Pressable: 'button',
+    ScrollView,
+    Animated: {
+      Text: 'span',
+      Value: class {
+        setValue(): void {}
+      },
+      loop: (animation: unknown) => animation,
+      sequence: settled,
+      timing: settled
+    },
+    StyleSheet: { create: (styles: unknown) => styles, hairlineWidth: 1 },
+    useWindowDimensions: () => ({ width: 400, height: 800 })
+  }
+})
+vi.mock('lucide-react-native', () => {
+  const icon = () => null
+  const names = ['Bot', 'Brain', 'Check', 'ChevronRight', 'Circle', 'CircleCheck', 'CircleDot']
+  const more = ['Eye', 'FileMinus2', 'FilePen', 'FilePlus2', 'Folder', 'Globe', 'ListChecks']
+  const rest = ['MessageSquareMore', 'Pencil', 'Plug', 'Search', 'SquareTerminal', 'Wrench']
+  return Object.fromEntries([...names, ...more, ...rest].map((name) => [name, icon]))
+})
+vi.mock('./mobile-native-chat-tool-styles', () => ({
+  toolStyles: {},
+  toolType: () => ({ row: {}, meta: {}, code: {} })
+}))
+vi.mock('../components/MobileSourceCopyButton', () => ({ MobileSourceCopyButton: () => null }))
+vi.mock('../platform/external-link', () => ({ openExternalLink: vi.fn() }))
+vi.mock('../components/inline-text-selection', () => ({ INLINE_TEXT_SELECTION: false }))
+
+const say = (id: string, role: 'user' | 'assistant', text: string): NativeChatMessage => ({
+  id,
+  role,
+  timestamp: null,
+  source: 'transcript',
+  blocks: [{ type: 'text', text }]
+})
+const edit = (n: number): NativeChatBlock => {
+  const lines = (word: string): string => Array.from({ length: 30 }, () => word).join('\n')
+  const input = { file_path: `f${n}.ts`, old_string: lines('old'), new_string: lines('new') }
+  return { type: 'tool-call', name: 'Edit', callId: `c${n}`, input }
+}
+const run = (n: number): NativeChatMessage[] => [
+  { ...say(`a${n}`, 'assistant', ''), blocks: [edit(n)] },
+  { ...say(`r${n}`, 'user', ''), blocks: [{ type: 'tool-result', callId: `c${n}`, output: 'ok' }] }
+]
+// An earlier turn, then a reply working silently through 40 edits.
+const chat = [say('u0', 'user', 'first'), say('x0', 'assistant', 'answer'), say('u1', 'user', 'go')]
+  .concat({
+    ...say('a1', 'assistant', 'On it'),
+    blocks: [{ type: 'text', text: 'On it' }, edit(1)]
+  })
+  .concat(run(1).slice(1), ...Array.from({ length: 39 }, (_, i) => run(i + 2)))
+
+type Box = { id: string; top: number; bottom: number; end: number }
+type Element = {
+  getAttribute: () => string
+  getBoundingClientRect: () => { top: number; bottom: number }
+  querySelectorAll: (selector: string) => Element[]
+}
+
+const oldHostTail = (): NativeChatMessage[] => JSON.parse(JSON.stringify(chat))
+const from = (id: string) => oldHostTail().slice(chat.findIndex((m) => m.id === id))
+
+/** The page with one 20-tall line per text, as the list's scrollable node counting its writes. */
+function page(tree: () => Node | Node[] | null) {
+  const boxes = (): Box[] => {
+    const out: Box[] = []
+    let y = 0
+    const walk = (node: Node | string): void => {
+      if (typeof node === 'string' || node.type === 'span') {
+        y += typeof node === 'string' ? 0 : 20
+        return
+      }
+      const at = out.push({ id: String(node.props.testID ?? ''), top: y, bottom: y, end: 0 }) - 1
+      node.children?.forEach(walk)
+      out[at] = { ...out[at]!, bottom: y, end: out.length }
+    }
+    walk({ type: 'page', props: {}, children: [tree() ?? []].flat() })
+    return out
+  }
+  const select = (all: Box[], from: number, to: number, selector: string): Element[] => {
+    const prefix = /\^="([^"]+)"/.exec(selector)?.[1] ?? '?'
+    return all.flatMap((box, at) =>
+      at >= from && at < to && box.id.startsWith(prefix)
+        ? [
+            {
+              getAttribute: () => box.id,
+              getBoundingClientRect: () => ({
+                top: box.top - node.scrollTop,
+                bottom: box.bottom - node.scrollTop
+              }),
+              querySelectorAll: (inner: string) => select(all, at + 1, box.end, inner)
+            }
+          ]
+        : []
+    )
+  }
+  let scrollTop = 0
+  const node = {
+    writes: 0,
+    get scrollTop(): number {
+      return scrollTop
+    },
+    set scrollTop(value: number) {
+      node.writes += 1
+      scrollTop = value
+    },
+    clientHeight: 200,
+    get scrollHeight(): number {
+      return boxes()[0]?.bottom ?? 0
+    },
+    getAttribute: () => null,
+    getBoundingClientRect: () => ({ top: 0, bottom: 200 }),
+    querySelectorAll: (selector: string): Element[] => select(boxes(), 0, Infinity, selector),
+    top: (id: string): number =>
+      (boxes().find((box) => box.id === id)?.top ?? Number.NaN) - node.scrollTop
+  }
+  return node
+}
+
+function Row({ message, rowKey }: { message: NativeChatMessage; rowKey: string }): ReactElement {
+  const { prose, tools } = splitNativeChatBlocks(message.blocks)
+  const words = prose.map((block, i) =>
+    h('span', { key: i }, block.type === 'text' ? block.text : '')
+  )
+  const run =
+    tools.length > 0 && h(ToolRun, { blocks: tools, defaultExpanded: false, expandChildren: false })
+  return h('div', { testID: mobileNativeChatRowId(rowKey) }, words, run)
+}
+
+type Scroller = ReturnType<typeof page>
+
+let shownKeys!: MobileNativeChatRowKeys
+
+function Chat(props: {
+  messages: NativeChatMessage[]
+  following: boolean
+  live: boolean
+  listRef: { current: { getScrollableNode: () => Scroller } }
+}): ReactElement {
+  const folded = useMemo(
+    () => foldMobileNativeChatMessages(props.messages, 'claude'),
+    [props.messages]
+  )
+  const keys = useMobileNativeChatRowKeys(folded, props.messages, 'chat')
+  shownKeys = keys
+  return h(
+    Fragment,
+    null,
+    h(MobileNativeChatScrollHold, {
+      rowKeys: keys,
+      isFollowing: () => props.following,
+      listRef: props.listRef
+    }),
+    h('div', { testID: 'header' }, h('span', null, 'Load earlier')),
+    folded.map((item) =>
+      h(Row, { key: keys.keyOf(item), message: item, rowKey: keys.keyOf(item) })
+    ),
+    props.live ? h('span', null, 'Working') : null
+  )
+}
+
+function mount(messages: NativeChatMessage[], options = { following: false, live: false }) {
+  let renderer!: ReactTestRenderer
+  act(() => {
+    renderer = create(h('div'))
+  })
+  const scroller = page(() => renderer.toJSON())
+  const listRef = { current: { getScrollableNode: () => scroller } }
+  const show = (next: NativeChatMessage[]): number => {
+    const before = scroller.writes
+    act(() => renderer.update(h(Chat, { ...options, messages: next, listRef })))
+    return scroller.writes - before
+  }
+  show(messages)
+  const find = (id: string) => renderer.root.find((n) => n.props.testID === id)
+  const press = (id: string) => act(() => find(id).findAllByType('button')[0]!.props.onPress())
+  const drawn = (id: string) => renderer.root.findAll((n) => n.props.testID === id).length
+  const lines = (id: string) => find(id).findAllByType('span').length
+  const rows = () =>
+    renderer.root
+      .findAll((n) => n.type === 'div' && String(n.props.testID).startsWith('chat-row:'))
+      .map((n) => n.props.testID)
+  return { scroller, show, press, drawn, lines, find, rows }
+}
+
+it('keeps the line a reader was on, its run open, when older messages join the run from an old host', () => {
+  // On a line inside the run, or at the top beside Load earlier while the window opens on a result
+  // that the run's older calls take in.
+  for (const atTop of [false, true]) {
+    const chat0 = mount(from('r31'))
+    chat0.press(mobileNativeChatRowId('a32'))
+    chat0.press('chat-member:call:c34')
+    const opened = chat0.lines('chat-member:call:c34')
+    chat0.scroller.scrollTop += chat0.scroller.top('chat-member:call:c34')
+    // An old host ignores the cursor and sends the whole tail again: new objects, the same ids.
+    for (const [older, first] of [
+      ['r21', 'c32'],
+      ['u0', 'c22']
+    ] as const) {
+      if (atTop) {
+        chat0.scroller.scrollTop = 0
+      }
+      const line = `chat-member:call:${atTop ? first : 'c34'}`
+      const top = chat0.scroller.top(line)
+      expect(chat0.show(from(older))).toBeLessThanOrEqual(1)
+      expect(chat0.scroller.top(line)).toBe(top)
+    }
+
+    // The run keeps its row, so the earlier turn sits above it and the run stays open.
+    expect(chat0.rows().slice(0, 3)).toEqual(['u0', 'x0', 'u1'].map(mobileNativeChatRowId))
+    expect(chat0.lines('chat-member:call:c34')).toBe(opened)
+    expect(chat0.drawn('chat-member:call:c1')).toBe(1)
+    // The result row the window opened on is now drawn by the run.
+    expect(shownKeys.current('r21')).toBe('a32')
+
+    // A reply and a send land after the run: what the reader had loaded stays drawn.
+    chat0.show([...oldHostTail(), say('done', 'assistant', 'Done'), say('ask', 'user', 'next')])
+    expect(chat0.drawn(mobileNativeChatRowId('a32'))).toBe(1)
+    expect(chat0.drawn('chat-member:call:c34')).toBe(1)
+  }
+
+  // The rows after the run stay put: collapsed, its header holds where it was, not in the result
+  // row's place; open, the line on screen holds while older calls join the run above it.
+  const later = Array.from({ length: 10 }, (_, i) => say(`t${i}`, 'user', 'later'))
+  for (const open of [false, true]) {
+    const tail = mount([...from('r21'), ...later])
+    if (open) {
+      tail.press(mobileNativeChatRowId('a22'))
+      tail.scroller.scrollTop += tail.scroller.top('chat-member:call:c27') + 40
+    }
+    const before = tail.scroller.top(mobileNativeChatRowId('t0'))
+    tail.show([...oldHostTail(), ...later])
+    expect(tail.scroller.top(mobileNativeChatRowId('t0'))).toBe(before)
+  }
+})
+
+it('leaves the view to iOS while it bounces the list past the top, and to a native list', () => {
+  for (const [os, scrollTop] of [
+    ['web', -15],
+    ['ios', 40]
+  ] as const) {
+    platform.OS = os
+    const chat0 = mount(from('r21'))
+    chat0.press(mobileNativeChatRowId('a22'))
+    chat0.scroller.scrollTop = scrollTop
+    expect(chat0.show(oldHostTail())).toBe(0)
+  }
+  platform.OS = 'web'
+})
+
+it('at the cap, a trim and an append of equal height hold a parked reader and leave a following one to follow', () => {
+  const rows = Array.from({ length: 13 }, (_, i) =>
+    say(`m${i}`, i % 2 ? 'assistant' : 'user', `message ${i}`)
+  )
+  for (const options of [
+    { following: true, live: false },
+    { following: true, live: true },
+    { following: false, live: false }
+  ]) {
+    const chat0 = mount(rows.slice(0, 12), options)
+    chat0.scroller.scrollTop = options.following ? chat0.scroller.scrollHeight - 200 : 50
+    const before = {
+      scrollTop: chat0.scroller.scrollTop,
+      m4: chat0.scroller.top(mobileNativeChatRowId('m4'))
+    }
+
+    const writes = chat0.show(rows.slice(1))
+
+    expect(writes).toBe(options.following ? 0 : 1)
+    if (options.following) {
+      expect(chat0.scroller.scrollTop).toBe(before.scrollTop)
+    } else {
+      expect(chat0.scroller.top(mobileNativeChatRowId('m4'))).toBe(before.m4)
+    }
+  }
+
+  // Trims split the top run: sequential calls leave a result above it; parallel calls (each call,
+  // then each output, or all outputs in one message) leave results below it. Results never take
+  // the run's key.
+  const output = (n: number): NativeChatMessage => ({
+    ...say(`o${n}`, 'user', ''),
+    role: 'tool',
+    blocks: [{ type: 'tool-result', callId: `c${n}`, output: 'ok' }]
+  })
+  const six = [1, 2, 3, 4, 5, 6]
+  const calls = (id: string) =>
+    six.map((n) => ({ ...say(`${id}${n}`, 'assistant', ''), blocks: [edit(n)] }))
+  const outputs = { ...output(1), id: 'U', blocks: six.flatMap((n) => output(n).blocks) }
+  for (const [source, head, orphan, last, absorbed] of [
+    [chat.slice(3, 15), 'a1', 'r1', 11, []],
+    [calls('p').concat(six.map(output)), 'p1', 'o1', 6, ['o1', 'o2', 'o3', 'o4']],
+    [calls('q').concat(outputs), 'q1', 'U', 6, ['U']]
+  ] as const) {
+    const top = mount([...source, ...rows])
+    top.press(mobileNativeChatRowId(head))
+    top.scroller.scrollTop = top.scroller.top('chat-member:call:c6') + top.scroller.scrollTop - 10
+    const trim = (trimmed: number) => {
+      top.show([...source.slice(trimmed), ...rows, say(`done${trimmed}`, 'assistant', 'Done')])
+      const run = top.find(mobileNativeChatRowId(head))
+      expect(run.findAll((n) => n.props.testID === 'chat-member:call:c6')).toHaveLength(1)
+      expect(top.scroller.top('chat-member:call:c6')).toBe(10)
+    }
+    trim(1)
+    expect(top.drawn(mobileNativeChatRowId(orphan))).toBe(1)
+    // A second single trim, then two at once.
+    trim(2)
+    trim(4)
+    // Paging back folds every result that was split off into the run again.
+    top.show([...source, ...rows, say('done4', 'assistant', 'Done')])
+    expect(absorbed.map(shownKeys.current)).toEqual(absorbed.map(() => head))
+    // Once its last call leaves, the run is gone; its outputs don't take its key.
+    top.show([...source.slice(last), ...rows, say('done', 'assistant', 'Done')])
+    expect(top.drawn(mobileNativeChatRowId(head))).toBe(0)
+  }
+
+  // A trim takes the very line the reader is on: the next one keeps its place.
+  const reader = mount([...chat.slice(3, 15), ...rows])
+  reader.press(mobileNativeChatRowId('a1'))
+  reader.scroller.scrollTop += reader.scroller.top('chat-member:call:c1')
+  const next = reader.scroller.top('chat-member:call:c2')
+  expect(next).toBeGreaterThan(0)
+  reader.show([...chat.slice(4, 15), ...rows, say('done', 'assistant', 'Done')])
+  expect(reader.scroller.top('chat-member:call:c2')).toBe(next)
+})
+
+it('a roster keeps its key when the fold moves it, and the rows the reader saw after it stay put', () => {
+  const sibling = (id: string): NativeChatMessage => ({
+    ...say(id, 'user', ''),
+    role: 'system',
+    blocks: [
+      { type: 'text', text: `Ran subagent ${id}` },
+      { type: 'subagent', id: `agent-${id}`, label: id, state: 'completed', groupId: 'turn-1' }
+    ]
+  })
+  const said = (name: string) =>
+    Array.from({ length: 12 }, (_, i) => say(`${name}${i}`, i % 2 ? 'assistant' : 'user', name))
+  const all = [...said('old'), sibling('s1'), ...said('mid'), sibling('s2'), ...said('new')]
+  const chat0 = mount(all.slice(25))
+  const tops = (ids: string[]) => ids.map((id) => chat0.scroller.top(mobileNativeChatRowId(id)))
+  // The roster first on screen: an older sibling joining moves it up to that sibling's place.
+  chat0.scroller.scrollTop = 20
+  const below = tops(['new0', 'new5'])
+  expect(chat0.show(all)).toBeLessThanOrEqual(1)
+  expect(tops(['new0', 'new5'])).toEqual(below)
+  expect(chat0.drawn(mobileNativeChatRowId('s2'))).toBe(1)
+  // And back: a trim of the first sibling moves the roster down to the second's place.
+  chat0.scroller.scrollTop += chat0.scroller.top(mobileNativeChatRowId('s2'))
+  const after = tops(['mid0', 'mid5'])
+  expect(chat0.show(all.slice(13))).toBeLessThanOrEqual(1)
+  expect(tops(['mid0', 'mid5'])).toEqual(after)
+  expect(chat0.drawn(mobileNativeChatRowId('s2'))).toBe(1)
+})
diff --git a/mobile/src/session/mobile-native-chat-row-keys.ts b/mobile/src/session/mobile-native-chat-row-keys.ts
new file mode 100644
index 00000000000..80836c1859f
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-row-keys.ts
@@ -0,0 +1,253 @@
+import { useLayoutEffect, useMemo, useRef } from 'react'
+import {
+  mobileNativeChatRunDescriptors,
+  type MobileNativeChatRunPresentation
+} from './mobile-native-chat-run-descriptors'
+import {
+  isSubagentGroupBlock,
+  isToolResultBlock,
+  type NativeChatBlock,
+  type NativeChatMessage
+} from '../../../src/shared/native-chat-types'
+
+/** Where each drawn row sits on the page. A folded row's id is its first message's, so older
+ *  messages joining a run would replace the row; its key stays while what it is made of draws. */
+export type MobileNativeChatRowKeys = {
+  /** The chat the keys belong to; nothing they held carries into another. */
+  scope: string
+  /** The source window's first message: it changes when a page, a cap trim or a replacement lands,
+   *  even while every row keeps its key. */
+  sourceHead: string | undefined
+  keyOf: (message: NativeChatMessage) => string
+  /** The key now drawing what a key of the last render drew; undefined once all of it left. */
+  current: (key: string) => string | undefined
+  /** The folded message a key's row is drawn for, which sets where the row sits: a roster keeps its
+   *  key while the fold moves it to an older sibling's place. */
+  placement: (key: string) => string
+}
+
+export type MobileNativeChatRowSources = { identity: string[]; content: string[] }
+type Sources = MobileNativeChatRowSources
+
+export type MobileNativeChatAssignedRows = {
+  rows: readonly NativeChatMessage[]
+  messages: readonly NativeChatMessage[]
+  keyById: ReadonlyMap<string, string>
+  /** Each row's sources, when that render worked them out. */
+  sources?: readonly Sources[]
+  prepareSources?: () => readonly Sources[]
+}
+type Assigned = MobileNativeChatAssignedRows
+
+/** The fold keeps its sources' block objects, so a block names the message it came from. */
+function blockOwners(messages: readonly NativeChatMessage[]): Map<NativeChatBlock, string> {
+  const owners = new Map<NativeChatBlock, string>()
+  for (const message of messages) {
+    for (const block of message.blocks) {
+      if (!owners.has(block)) {
+        owners.set(block, message.id)
+      }
+    }
+  }
+  return owners
+}
+
+/** What a row draws, by message and kind, and which of it makes the row what it is: a run is
+ *  its assistant and its calls. Its results are content only, so a result left on a row of its
+ *  own never takes the run's key. The fold makes a roster's group block; its group stands in. */
+function sourcesOf(row: NativeChatMessage, owners: Map<NativeChatBlock, string>): Sources {
+  const own = new Set<string>()
+  const results = new Set<string>()
+  for (const block of row.blocks) {
+    const owner = owners.get(block)
+    if (isSubagentGroupBlock(block)) {
+      own.add(`subagent-group:${block.groupId}`)
+    } else if (owner !== undefined && isToolResultBlock(block)) {
+      results.add(`result:${owner}`)
+    } else if (owner !== undefined) {
+      own.add(`body:${owner}`)
+    }
+  }
+  const content = [...own, ...results]
+  const identity = own.size > 0 ? [...own] : results.size > 0 ? [...results] : [`body:${row.id}`]
+  return { identity, content: content.length > 0 ? content : identity }
+}
+
+/** Physical rows and displayed runs attribute against the same raw snapshot, only when needed. */
+export function prepareMobileNativeChatRowSources(messages: readonly NativeChatMessage[]) {
+  let owners: Map<NativeChatBlock, string> | undefined
+  const cache = new WeakMap<NativeChatMessage, Sources>()
+  return (row: NativeChatMessage): Sources => {
+    let sources = cache.get(row)
+    if (!sources) {
+      sources = sourcesOf(row, (owners ??= blockOwners(messages)))
+      cache.set(row, sources)
+    }
+    return sources
+  }
+}
+
+function sourcesByRow(
+  rows: readonly NativeChatMessage[],
+  messages: readonly NativeChatMessage[],
+  scopeOf?: (row: NativeChatMessage) => string | undefined
+): Sources[] {
+  const owners = blockOwners(messages)
+  return rows.map((row) => {
+    const sources = sourcesOf(row, owners)
+    if (!scopeOf) {
+      return sources
+    }
+    const scoped = (source: string) => `${source}\0${scopeOf(row) ?? ''}`
+    return { identity: sources.identity.map(scoped), content: sources.content.map(scoped) }
+  })
+}
+
+export function assignMobileNativeChatRowKeys(
+  previous: Assigned | null,
+  rows: readonly NativeChatMessage[],
+  messages: readonly NativeChatMessage[],
+  fresh?: () => string,
+  scopeOf?: (row: NativeChatMessage) => string | undefined,
+  preparedSources?: () => readonly Sources[]
+): Pick<Assigned, 'sources'> & {
+  keyById: Map<string, string>
+  moved: Map<string, string | undefined>
+} {
+  const keyById = new Map<string, string>()
+  const taken = new Set<string>()
+  const take = (row: NativeChatMessage, key: string): void => {
+    keyById.set(row.id, key)
+    taken.add(key)
+  }
+  const ids = new Set(rows.map((row) => row.id))
+  let before: readonly Sources[] = []
+  let now: readonly Sources[] | undefined
+  const current = () => (now ??= preparedSources?.() ?? sourcesByRow(rows, messages, scopeOf))
+  if (fresh) {
+    current()
+  }
+  if (!fresh && previous?.rows.every((row) => ids.has(row.id))) {
+    // Nothing left: every row keeps its key.
+    for (const row of rows) {
+      const key = previous.keyById.get(row.id)
+      if (key !== undefined) {
+        take(row, key)
+      }
+    }
+  } else if (previous) {
+    before =
+      previous.sources ??
+      previous.prepareSources?.() ??
+      sourcesByRow(previous.rows, previous.messages)
+    current()
+    const was = new Map<string, number>()
+    before.forEach(({ identity }, at) => identity.forEach((source) => was.set(source, at)))
+    // A row continues the one row its identity came from, if that row's went nowhere else. Two
+    // would be one key for two rows, so neither inherits rather than one being picked by position.
+    const origins = current().map(
+      ({ identity }) => new Set(identity.flatMap((s) => was.get(s) ?? []))
+    )
+    const heirs = new Map<number, number>()
+    origins.forEach((from) => from.forEach((at) => heirs.set(at, (heirs.get(at) ?? 0) + 1)))
+    origins.forEach((from, at) => {
+      const [origin] = from
+      const only = origin !== undefined && from.size === 1 && heirs.get(origin) === 1
+      const key = only ? previous.keyById.get(previous.rows[origin]!.id) : undefined
+      if (key !== undefined) {
+        take(rows[at]!, key)
+      }
+    })
+  }
+  for (const row of rows.filter((unkeyed) => !keyById.has(unkeyed.id))) {
+    let key = fresh?.() ?? row.id
+    for (let n = 1; taken.has(key); n += 1) {
+      key = `${row.id}~${n}`
+    }
+    take(row, key)
+  }
+  // A key no row kept names the first row that took in what it drew. Results left on rows of their
+  // own when a run's last call went name none: the run ended, and its key goes with it.
+  const drawnAt = new Map<string, number>()
+  now?.forEach(({ identity, content }, at) => {
+    if (!identity[0]!.startsWith('result:')) {
+      content.forEach((s) => {
+        if (!drawnAt.has(s)) {
+          drawnAt.set(s, at)
+        }
+      })
+    }
+  })
+  const moved = new Map<string, string | undefined>()
+  before.forEach(({ content }, at) => {
+    const key = previous?.keyById.get(previous.rows[at]!.id)
+    if (key !== undefined && !taken.has(key)) {
+      const holder = rows[Math.min(...content.map((s) => drawnAt.get(s) ?? Infinity))]
+      moved.set(key, holder && keyById.get(holder.id))
+    }
+  })
+  return { keyById, moved, ...(now ? { sources: now } : {}) }
+}
+
+/** Row keys for one shown chat, against the last committed render only, so what a key held dies
+ *  with the rows that held it. */
+export function useMobileNativeChatRowKeys(
+  rows: readonly NativeChatMessage[],
+  messages: readonly NativeChatMessage[],
+  scope: string,
+  presentation?: MobileNativeChatRunPresentation
+): MobileNativeChatRowKeys & {
+  runOwners: ReadonlyMap<string, string>
+  runPlacements: ReadonlyMap<string, string>
+} {
+  // Written at commit: a render React discards must not become the next one's last render.
+  const committed = useRef<
+    (Assigned & { scope: string; displayed: Assigned; serial: number }) | null
+  >(null)
+  const assigned = useMemo(() => {
+    const previous = committed.current?.scope === scope ? committed.current : null
+    const sourceOf = prepareMobileNativeChatRowSources(messages)
+    const prepareSources = () => rows.map(sourceOf)
+    const physical = assignMobileNativeChatRowKeys(
+      previous,
+      rows,
+      messages,
+      undefined,
+      undefined,
+      prepareSources
+    )
+    const runs = presentation ? mobileNativeChatRunDescriptors(presentation, sourceOf) : []
+    const heads = runs.map((run) => run.row)
+    let serial = previous?.serial ?? 0
+    const displayed = {
+      rows: heads,
+      messages,
+      ...assignMobileNativeChatRowKeys(
+        previous?.displayed ?? null,
+        heads,
+        messages,
+        () => `display-run:${serial++}`,
+        undefined,
+        () => runs.map((run) => run.sources)
+      )
+    }
+    const runPlacements = new Map(Array.from(displayed.keyById, ([row, owner]) => [owner, row]))
+    return { scope, rows, messages, prepareSources, ...physical, displayed, serial, runPlacements }
+  }, [rows, messages, scope, presentation])
+  useLayoutEffect(() => {
+    committed.current = assigned
+  }, [assigned])
+  return useMemo(() => {
+    let idByKey: Map<string, string> | undefined
+    return {
+      runOwners: assigned.displayed.keyById,
+      runPlacements: assigned.runPlacements,
+      scope: assigned.scope,
+      sourceHead: assigned.messages[0]?.id,
+      keyOf: (message: NativeChatMessage) => assigned.keyById.get(message.id) ?? message.id,
+      current: (key: string) => (assigned.moved.has(key) ? assigned.moved.get(key) : key),
+      placement: (key: string) =>
+        (idByKey ??= new Map(Array.from(assigned.keyById, ([id, k]) => [k, id]))).get(key) ?? key
+    }
+  }, [assigned])
+}
diff --git a/mobile/src/session/mobile-native-chat-run-descriptors.ts b/mobile/src/session/mobile-native-chat-run-descriptors.ts
new file mode 100644
index 00000000000..743cbb6087d
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-run-descriptors.ts
@@ -0,0 +1,48 @@
+import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
+import type { NativeChatResolvedPrompt } from '../../../src/shared/native-chat-resolution-receipt'
+import { splitNativeChatBlocks } from '../../../src/shared/native-chat-tool-fold'
+import { nativeChatWorkRunEntries } from '../../../src/shared/native-chat-work-run'
+import { nativeChatAskRunBlocks } from '../../../src/shared/native-chat-ask-row'
+import type { MobileNativeChatWorkRuns } from './use-mobile-native-chat-transcript-rows'
+import type { MobileNativeChatRowSources } from './mobile-native-chat-row-keys'
+
+export type MobileNativeChatRunPresentation = {
+  rows: readonly NativeChatMessage[]
+  workRuns: MobileNativeChatWorkRuns
+  turnKeys: readonly (string | undefined)[]
+  receipts?: ReadonlyMap<string, NativeChatResolvedPrompt> | null
+}
+
+/** Describe the runs the existing presentation draws, sharing physical-row source attribution. */
+export function mobileNativeChatRunDescriptors(
+  { rows, workRuns, turnKeys, receipts }: MobileNativeChatRunPresentation,
+  sourceOf: (row: NativeChatMessage) => MobileNativeChatRowSources
+) {
+  return rows.flatMap((row, index) => {
+    if (workRuns.joined.has(index) || receipts?.has(row.id)) {
+      return []
+    }
+    const members = workRuns.heads.get(index)
+    if (row.role === 'reasoning' && !members) {
+      return []
+    }
+    const tools = members
+      ? nativeChatWorkRunEntries(members).blocks
+      : splitNativeChatBlocks(row.blocks).tools
+    if (nativeChatAskRunBlocks(tools).work.length === 0) {
+      return []
+    }
+    const content = [...new Set((members ?? [row]).flatMap((member) => sourceOf(member).content))]
+    const own = content.filter((source) => !source.startsWith('result:'))
+    const scoped = (source: string) => `${source}\0${turnKeys[index] ?? ''}`
+    return [
+      {
+        row,
+        sources: {
+          identity: (own.length ? own : content).map(scoped),
+          content: content.map(scoped)
+        }
+      }
+    ]
+  })
+}
diff --git a/mobile/src/session/mobile-native-chat-scroll-ownership.test.tsx b/mobile/src/session/mobile-native-chat-scroll-ownership.test.tsx
new file mode 100644
index 00000000000..c3228f22758
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-scroll-ownership.test.tsx
@@ -0,0 +1,527 @@
+// @vitest-environment happy-dom
+import {
+  act,
+  createElement as h,
+  Fragment,
+  startTransition,
+  Suspense,
+  useLayoutEffect,
+  useMemo,
+  useRef,
+  type ReactNode
+} from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { afterEach, expect, it, vi } from 'vitest'
+import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
+import { foldToolMessages } from '../../../src/shared/native-chat-tool-fold'
+import { MobileNativeChatMessage } from './MobileNativeChatMessage'
+import { MobileNativeChatScrollHold } from './MobileNativeChatScrollHold'
+import { MobileNativeChatPageRows } from './mobile-native-chat-page-rows'
+import { MobileNativeChatPageMotion } from './mobile-native-chat-page-motion'
+import {
+  mobileNativeChatScrollFrame,
+  mobileNativeChatReadingParts,
+  mobileNativeChatVisible,
+  MobileNativeChatScrollRoots
+} from './mobile-native-chat-scroll-roots'
+import {
+  MobileNativeChatDisclosureContext,
+  useMobileNativeChatDisclosures,
+  type MobileNativeChatDisclosureStore
+} from './mobile-native-chat-disclosure-store'
+import { useMobileNativeChatRowKeys } from './mobile-native-chat-row-keys'
+import { useMobileNativeChatTurnDisclosure } from './use-mobile-native-chat-turn-disclosure'
+
+vi.mock('react-native', async () => {
+  const React = await import('react')
+  const View = (p: {
+    children?: ReactNode
+    testID?: string
+    onPress?: () => void
+    accessibilityLiveRegion?: string
+  }) =>
+    React.createElement(
+      'div',
+      { 'data-testid': p.testID, onClick: p.onPress, 'data-live': p.accessibilityLiveRegion },
+      p.children
+    )
+  const ScrollView = React.forwardRef((p: { children?: ReactNode }, ref) => {
+    const node = React.useRef<HTMLDivElement>(null)
+    React.useImperativeHandle(ref, () => ({
+      getScrollableNode: () => node.current,
+      getInnerViewNode: () => node.current?.firstElementChild
+    }))
+    return React.createElement(
+      'div',
+      { ref: node, className: 'viewport' },
+      React.createElement('div', null, p.children)
+    )
+  })
+  const animation = () => ({ start() {}, stop() {} })
+  return {
+    View,
+    Text: View,
+    Pressable: View,
+    ScrollView,
+    Image: View,
+    Platform: { OS: 'web' },
+    StyleSheet: { create: (s: unknown) => s, hairlineWidth: 1 },
+    useWindowDimensions: () => ({ width: 400, height: 800 }),
+    Animated: {
+      Text: View,
+      Value: class {
+        setValue() {}
+      },
+      loop: animation,
+      sequence: animation,
+      timing: animation
+    }
+  }
+})
+vi.mock('lucide-react-native', () =>
+  Object.fromEntries(
+    'ArrowUp Bot Brain Check ChevronDown ChevronRight Copy Eye FileMinus2 FilePen FilePlus2 Folder Globe ListChecks MessageSquareMore Pencil Plug Search SquareChevronRight SquareTerminal Wrench Circle CircleCheck CircleDot'
+      .split(' ')
+      .map((key) => [key, () => null])
+  )
+)
+vi.mock('../components/MobileMarkdown', () => ({ MobileMarkdown: () => null }))
+vi.mock('../components/MobileSourceCopyButton', () => ({ MobileSourceCopyButton: () => null }))
+vi.mock('../platform/external-link', () => ({ openExternalLink: vi.fn() }))
+vi.mock('../components/inline-text-selection', () => ({ INLINE_TEXT_SELECTION: false }))
+
+let renderer: Root | undefined
+let container: HTMLDivElement
+let page: HTMLElement
+let frameShift = 0
+let roots: MobileNativeChatScrollRoots
+let owners: (string | undefined)[]
+let projected: (string | undefined)[]
+let store: MobileNativeChatDisclosureStore
+const abandoned = new Promise<void>(() => {})
+const correctPage = vi.fn((drift: number) => {
+  page.scrollTop += drift
+})
+const msg = (
+  id: string,
+  blocks: NativeChatMessage['blocks'],
+  role: NativeChatMessage['role'] = 'assistant'
+): NativeChatMessage => ({ id, blocks, role, timestamp: null, source: 'transcript' })
+const a = msg(
+  'a',
+  Array.from({ length: 6 }, (_, i) => ({
+    type: 'tool-call',
+    callId: `c${i}`,
+    name: 'Bash',
+    input: { command: `command ${i} ${'argument '.repeat(20)}` }
+  }))
+)
+const thought = msg('r', [{ type: 'text', text: 'reason' }], 'reasoning')
+const user = msg('u', [{ type: 'text', text: 'go' }], 'user')
+const b = msg('b', [{ type: 'tool-call', callId: 'b', name: 'Bash', input: { command: 'b' } }])
+function reader(node: Element, top: number) {
+  node.dispatchEvent(new Event('touchstart'))
+  node.scrollTop = top
+  node.dispatchEvent(new Event('scroll'))
+  node.dispatchEvent(new Event('touchend'))
+}
+function members(root: Element): Element[] {
+  return Array.from(root.querySelectorAll('[data-testid^="chat-member:"]')).filter(
+    (node) => !mobileNativeChatScrollFrame(node, root)
+  )
+}
+function rect(node: Element): DOMRect {
+  const viewport = node.closest('[data-chat-scroll-root]')
+  let top = 0
+  let height = 1000
+  if (node === page) {
+    return DOMRect.fromRect({ y: 100, height: 200, width: 400 })
+  }
+  if (viewport === node) {
+    const parent = node.parentElement?.closest('[data-chat-scroll-root]')
+    top = parent
+      ? rect(node.parentElement!.closest('[data-testid^="chat-member:"]') ?? parent).top + 20
+      : 40 + frameShift - page.scrollTop
+    height = 160
+  } else if (viewport) {
+    const member = node.closest('[data-testid^="chat-member:"]')
+    top =
+      rect(viewport).top +
+      Math.max(0, members(viewport).indexOf(member ?? node)) * 60 -
+      viewport.scrollTop
+    height = 60
+  } else if (node.closest('[data-live], [data-testid="chat-row:u"]')) {
+    top = -page.scrollTop
+    height = 20
+  } else {
+    top = -page.scrollTop
+  }
+  return DOMRect.fromRect({ y: top, height, width: 400 })
+}
+function Shift({ value }: { value: number }): null {
+  useLayoutEffect(() => {
+    frameShift = value
+  }, [value])
+  return null
+}
+function Chat({
+  rows,
+  tools = true,
+  shown = true,
+  scope = 'chat',
+  shift = 0,
+  suspend = false,
+  structured = true,
+  working = false
+}: {
+  rows: NativeChatMessage[]
+  tools?: boolean
+  shown?: boolean
+  scope?: string
+  shift?: number
+  suspend?: boolean
+  structured?: boolean
+  working?: boolean
+}) {
+  const current = useMobileNativeChatDisclosures(scope)
+  const drawn = useMemo(() => (structured ? rows : foldToolMessages(rows)), [rows, structured])
+  const turns = useMobileNativeChatTurnDisclosure({
+    messages: drawn,
+    enabled: structured,
+    isWorking: working,
+    scopeKey: scope
+  })
+  const keys = useMobileNativeChatRowKeys(drawn, rows, scope, turns.presentation)
+  const ref = useRef({
+    getScrollableNode: () => page,
+    keepInPlace: correctPage
+  })
+  useLayoutEffect(() => {
+    store = current
+    roots = current.roots
+    owners = drawn.map((row) => keys.runOwners.get(row.id))
+  })
+  if (suspend) {
+    projected = drawn.map((row) => keys.runOwners.get(row.id))
+    throw abandoned
+  }
+  return h(
+    MobileNativeChatDisclosureContext.Provider,
+    { value: current },
+    h(
+      MobileNativeChatScrollHold,
+      {
+        rowKeys: keys,
+        roots: current.roots,
+        runPlacements: keys.runPlacements,
+        layoutKey: String(tools),
+        listRef: ref,
+        isFollowing: () => false
+      },
+      h(Shift, { value: shift }),
+      h(
+        Fragment,
+        { key: scope },
+        shown &&
+          drawn.map((message, i) =>
+            h(MobileNativeChatMessage, {
+              key: keys.keyOf(message),
+              message,
+              rowKey: keys.keyOf(message),
+              ...turns.resolveRow(i, message),
+              runOwner: keys.runOwners.get(message.id),
+              structuredActivityUi: structured,
+              toolsExpanded: tools
+            })
+          )
+      )
+    )
+  )
+}
+function mount(structured = true) {
+  vi.useFakeTimers()
+  vi.stubGlobal('IS_REACT_ACT_ENVIRONMENT', true)
+  vi.stubGlobal('navigator', { userAgent: 'AppleWebKit Safari' })
+  container = document.createElement('div')
+  page = document.createElement('main')
+  page.style.overflowY = 'auto'
+  document.body.append(page)
+  page.append(container)
+  vi.spyOn(Element.prototype, 'getBoundingClientRect').mockImplementation(function (this: Element) {
+    return rect(this)
+  })
+  vi.spyOn(HTMLElement.prototype, 'clientHeight', 'get').mockReturnValue(160)
+  vi.spyOn(Element.prototype, 'scrollHeight', 'get').mockImplementation(function (this: Element) {
+    return this.getAttribute('data-short')
+      ? 80
+      : members(this).length * 60 +
+          400 +
+          this.querySelectorAll('.viewport').length * 60 +
+          Number(this.getAttribute('data-growth') ?? 0)
+  })
+  renderer = createRoot(container)
+  return (rows: NativeChatMessage[], rest: Partial<Parameters<typeof Chat>[0]> = {}) => {
+    const render = () =>
+      renderer!.render(h(Suspense, { fallback: null }, h(Chat, { rows, structured, ...rest })))
+    act(() => (rest.suspend ? startTransition(render) : render()))
+    act(() => vi.advanceTimersByTime(20))
+  }
+}
+afterEach(() => {
+  act(() => renderer?.unmount())
+  page?.remove()
+  renderer = undefined
+  frameShift = 0
+  correctPage.mockClear()
+  vi.useRealTimers()
+  vi.restoreAllMocks()
+  vi.unstubAllGlobals()
+})
+
+it('keeps real structured runs and nested offsets under their own viewport across reheading', () => {
+  const draw = mount()
+  draw([user, a])
+  const owner = owners[1]
+  const run = container.querySelector('[data-chat-scroll-root]')
+  if (!(run instanceof HTMLElement)) {
+    throw new Error('missing run viewport')
+  }
+  const detail = run.querySelector('[data-chat-scroll-root]')
+  if (!(detail instanceof HTMLElement)) {
+    throw new Error('missing command viewport')
+  }
+  const row = run.closest('[data-testid^="chat-row:"]')!
+  const rows = new MobileNativeChatPageRows()
+  rows.ref('a')(row)
+  rows.takeAnchor(page, ['a'], [0, 1], true)
+  reader(run, 100)
+  reader(detail, 35)
+  act(() => vi.advanceTimersByTime(160))
+  roots.restoreAll()
+  expect(rows.placeShift(page)).toBe(0)
+  expect(page.scrollTop).toBe(0)
+  expect(correctPage).not.toHaveBeenCalled()
+  const clipped = run.querySelector('[data-testid="chat-member:call:c0"]')!
+  expect(mobileNativeChatVisible(clipped, page)).toBe(false)
+  expect(mobileNativeChatReadingParts(row)).toContain(run)
+  expect(mobileNativeChatReadingParts(row)).not.toContain(clipped)
+  const anchor = run.querySelector('[data-testid="chat-member:call:c3"]')!
+  const offset = rect(anchor).top - rect(run).top
+  draw([user, thought, a], { shift: 80 })
+  expect(owners[1]).toBe(owner)
+  const restored = container.querySelector('[data-chat-scroll-root]')!
+  expect(
+    rect(restored.querySelector('[data-testid="chat-member:call:c3"]')!).top - rect(restored).top
+  ).toBe(offset)
+  expect(restored.querySelector('[data-chat-scroll-root]')?.scrollTop).toBe(35)
+  expect(page.scrollTop).toBe(80)
+  expect(correctPage).toHaveBeenCalledExactlyOnceWith(80, false)
+  const top = restored.scrollTop
+  draw([user, thought, a], { shown: false, shift: 80 })
+  draw([user, thought, a], { shift: 80 })
+  expect(container.querySelector('[data-chat-scroll-root]')?.scrollTop).toBe(top)
+  const observer = { observe: vi.fn(), unobserve: vi.fn(), disconnect: vi.fn() }
+  roots.observeWith(observer)
+  expect(observer.observe).toHaveBeenCalledWith(container.querySelector('[data-chat-scroll-root]'))
+  const late = document.createElement('div')
+  const content = document.createElement('div')
+  late.append(content)
+  container.append(late)
+  late.setAttribute('data-short', 'yes')
+  store.runScroll.set('late', { top: 37, followsEnd: false, member: 'missing', offset: 10 })
+  const stop = roots.register('late', late, content, 'late', 'late', false)
+  expect(late.scrollHeight).toBeLessThan(late.clientHeight)
+  expect(observer.observe).toHaveBeenCalledWith(content)
+  roots.capture(new Set(), false)
+  expect(store.runScroll.get('late')?.top).toBe(37)
+  late.removeAttribute('data-short')
+  roots.restoreAll()
+  expect(late.scrollTop).toBe(37)
+  expect(store.runScroll.get('late')?.member).toBeUndefined()
+  const removed = vi.spyOn(late, 'removeEventListener')
+  const replacement = document.createElement('div')
+  late.replaceChildren(replacement)
+  const replaced = roots.register('late', late, replacement, 'late', 'late', false)
+  observer.unobserve.mockClear()
+  stop()
+  expect(roots.frame('late')).toBe(late)
+  expect(observer.unobserve.mock.calls.some(([node]) => node === late)).toBe(false)
+  expect(observer.unobserve.mock.calls.some(([node]) => node === replacement)).toBe(false)
+  late.remove()
+  roots.restoreAll()
+  replaced()
+  expect(roots.frame('late')).toBeUndefined()
+  expect(observer.unobserve.mock.calls.some(([node]) => node === content)).toBe(true)
+  expect(removed).toHaveBeenCalledWith('scroll', expect.any(Function))
+})
+
+it.each([true, false])(
+  'issues fresh displayed owners through split and merge instead of reviving retired choices (structured=%s)',
+  (structured) => {
+    const draw = mount(structured)
+    draw([user, a, b], { working: true })
+    const original = owners[1]
+    const oldKey = `run:${original}:true`
+    act(() => store.write(oldKey, false))
+    store.runScroll.set(oldKey, { top: 111, followsEnd: false })
+    const splitRows = [
+      user,
+      a,
+      msg('break', [{ type: 'text', text: 'answer' }], structured ? 'assistant' : 'user'),
+      b
+    ]
+    const registry = roots
+    draw(splitRows, { suspend: true, working: true })
+    expect(projected[1]).not.toBe(original)
+    expect(owners[1]).toBe(original)
+    expect(roots).toBe(registry)
+    expect(store.runScroll.get(oldKey)?.top).toBe(111)
+    const tentative = [...projected]
+    draw(splitRows, { working: true })
+    const split = [owners[1], owners[3]]
+    expect(new Set([original, ...split]).size).toBe(3)
+    expect(owners).toEqual(tentative)
+    const reused = roots.frame(`run:${split[0]}`)!
+    reader(reused, 40)
+    draw([user, a, b])
+    expect([original, ...split]).not.toContain(owners[1])
+    expect(store.read(oldKey)).toBe(false)
+    expect(store.runScroll.get(oldKey)?.top).toBe(111)
+    expect(roots.frame(`run:${owners[1]}`)).toBe(reused)
+    expect(reused.scrollTop).toBe(40)
+    expect(store.runScroll.get(`run:${owners[1]}:true`)?.followsEnd).toBe(false)
+  }
+)
+
+it('waits for simultaneous inner rest, releases on close/scope change, and separates work-follow from reader chaining', async () => {
+  const draw = mount()
+  draw([user, a])
+  const run = container.querySelector('[data-chat-scroll-root]')!
+  const detail = run.querySelector('[data-chat-scroll-root]')!
+  vi.stubGlobal('navigator', { userAgent: 'AppleWebKit Chrome' })
+  const pageMotion = new MobileNativeChatPageMotion(() => {})
+  const detach = pageMotion.attach(page)
+  pageMotion.reconciled(100, 1000)
+  run.dispatchEvent(new Event('touchstart'))
+  run.scrollTop = 100
+  run.dispatchEvent(new Event('scroll'))
+  let settled = false
+  const waiting = roots.settled(pageMotion).then(() => {
+    settled = true
+  })
+  await Promise.resolve()
+  expect(pageMotion.settled()).toBe(true)
+  expect(settled).toBe(false)
+  detail.dispatchEvent(new Event('touchstart'))
+  detail.scrollTop = 35
+  detail.dispatchEvent(new Event('scroll'))
+  run.dispatchEvent(new Event('touchend'))
+  await vi.advanceTimersByTimeAsync(160)
+  expect(settled).toBe(false)
+  detail.dispatchEvent(new Event('touchend'))
+  await vi.advanceTimersByTimeAsync(0)
+  await waiting
+  reader(run, run.scrollHeight - run.clientHeight - 20)
+  await vi.advanceTimersByTimeAsync(160)
+  const parked = run.scrollTop
+  run.setAttribute('data-growth', '60')
+  roots.restoreAll()
+  expect(run.scrollTop).toBe(parked)
+  draw([user, a, b])
+  expect(run.scrollTop).toBe(run.scrollHeight - run.clientHeight)
+  run.dispatchEvent(new Event('scroll'))
+  await roots.settled(pageMotion)
+  expect(pageMotion.scrolled(100, 1000, () => false).by).toBe('none')
+  run.dispatchEvent(new WheelEvent('wheel', { deltaY: -10, bubbles: true }))
+  expect(pageMotion.scrolled(90, 1000, () => false).by).toBe('reader')
+  pageMotion.release()
+  run.dispatchEvent(new Event('touchstart'))
+  const closing = roots.settled(pageMotion)
+  act(() => container.querySelector<HTMLElement>('[data-live]')!.click())
+  await closing
+  expect(run.hasAttribute('data-chat-scroll-root')).toBe(false)
+  draw([user, a], { scope: 'intermediate' })
+  container.querySelector('[data-chat-scroll-root]')!.dispatchEvent(new Event('touchstart'))
+  const leaving = roots.settled(pageMotion)
+  draw([user, a], { scope: 'other' })
+  await leaving
+  vi.stubGlobal('navigator', { userAgent: 'AppleWebKit Safari' })
+  draw([user, a], { scope: 'other', tools: false, working: true })
+  act(() => container.querySelector<HTMLElement>('[data-live]')!.click())
+  const key = `run:${owners[1]}`
+  const live = roots.frame(key)!
+  const end = live.scrollTop
+  expect(end).toBe(live.scrollHeight - live.clientHeight)
+  const previous = store.runScroll.get(`${key}:false`)!
+  draw([user, a], { scope: 'other', working: true, shift: 40 })
+  expect(roots.frame(key)).toBe(live)
+  expect(live.scrollTop).toBe(end)
+  expect(live.scrollTop).toBeLessThan(live.scrollHeight - live.clientHeight)
+  expect(correctPage).toHaveBeenCalledExactlyOnceWith(40, true)
+  reader(live, end - 100)
+  draw([user, a], { scope: 'other', tools: false, working: true, shift: 40 })
+  expect(live.scrollTop).toBe(end - 100)
+  expect(store.runScroll.get(`${key}:false`)?.followsEnd).toBe(false)
+  expect(previous.followsEnd).toBe(true)
+  reader(live, live.scrollHeight - live.clientHeight - 20)
+  await vi.advanceTimersByTimeAsync(160)
+  draw([user, a, b], { scope: 'other', tools: false, working: true, shift: 40 })
+  expect(live.scrollTop).toBe(live.scrollHeight - live.clientHeight)
+  draw([user, a, b], { scope: 'other', tools: false, working: true, shown: false, shift: 40 })
+  store.runScroll.set(`${key}:false`, { top: 37, followsEnd: false })
+  draw([user, a, b], { scope: 'other', tools: false, working: true, shift: 40 })
+  expect(roots.frame(key)?.scrollTop).toBe(37)
+  detach()
+  pageMotion.release()
+})
+
+it('keeps the actual changed task checklist through eviction and Tools, isolated by chat', () => {
+  const draw = mount()
+  const tasks = msg(
+    'tasks',
+    [false, true].map((done) => ({
+      type: 'tool-call',
+      callId: String(done),
+      name: 'TodoWrite',
+      input: {
+        todos: [
+          { content: 'Remember', status: done ? 'completed' : 'pending', activeForm: 'Remembering' }
+        ]
+      }
+    }))
+  )
+  draw([user, tasks])
+  const count = () => container.textContent?.match(/Remember/g)?.length ?? 0
+  const before = count()
+  const disclosure = Array.from(container.querySelectorAll('div')).findLast(
+    (node) => node.textContent === 'Full task list'
+  )
+  if (!disclosure) {
+    throw new Error('missing changed-task disclosure')
+  }
+  act(() => disclosure.click())
+  expect(count()).toBe(before + 1)
+  draw([user, tasks], { shown: false })
+  draw([user, tasks])
+  expect(count()).toBe(before + 1)
+  draw([user, tasks], { tools: false })
+  draw([user, tasks])
+  expect(count()).toBe(before + 1)
+  draw([user, tasks], { scope: 'different' })
+  expect(count()).toBe(before)
+})
+
+it("forgets a closed tool line's nested command and output positions, not its neighbours'", () => {
+  const at = { top: 30, followsEnd: false }
+  const memory = new Map(
+    ['run:o:true', 'run:o:true/line:a:command', 'run:o:true/line:a:output', 'line:a:command']
+      .concat(['run:o:true/line:ab:command', 'diff:src/line:a.ts'])
+      .map((address) => [address, at] as const)
+  )
+  new MobileNativeChatScrollRoots(memory, 10).forget('line:a')
+  expect([...memory.keys()]).toEqual([
+    'run:o:true',
+    'run:o:true/line:ab:command',
+    'diff:src/line:a.ts'
+  ])
+})
diff --git a/mobile/src/session/mobile-native-chat-scroll-root-handle.ts b/mobile/src/session/mobile-native-chat-scroll-root-handle.ts
new file mode 100644
index 00000000000..e8f34f44888
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-scroll-root-handle.ts
@@ -0,0 +1,104 @@
+import type { MobileNativeChatPageMotion } from './mobile-native-chat-page-motion'
+import type { MobileNativeChatPageAnchoring } from './mobile-native-chat-page-anchoring'
+
+export type MobileNativeChatRootPosition = {
+  top: number
+  followsEnd: boolean
+  member?: string
+  offset?: number
+}
+
+type Root = {
+  id: string
+  address: string
+  owner: string
+  node: HTMLElement
+  content: Element
+  position: MobileNativeChatRootPosition
+  work: number | undefined
+  nextWork: number | undefined
+  fresh: boolean
+  motion: MobileNativeChatPageMotion
+  anchoring: MobileNativeChatPageAnchoring
+  detach: () => void
+}
+export type { Root as MobileNativeChatScrollRootHandle }
+
+const owners = new WeakMap<Element, Root>()
+const ROOT = 'data-chat-scroll-root'
+export const mobileNativeChatScrollRootKey = (node: Element): string | undefined =>
+  owners.get(node)?.id
+
+/** The first viewport crossed from the requesting owner, never a deeper descendant's frame. */
+export function mobileNativeChatScrollFrame(node: Element, within: Element): Element | undefined {
+  let frame: Element | undefined
+  for (let at: Element | null = node; at && at !== within; at = at.parentElement) {
+    if (owners.has(at)) {
+      frame = at
+    }
+  }
+  return frame
+}
+
+export function mobileNativeChatVisible(node: Element, root: Element): boolean {
+  const box = node.getBoundingClientRect()
+  let { top, bottom } = root.getBoundingClientRect()
+  for (let at = node.parentElement; at; at = at.parentElement) {
+    if (
+      at === root ||
+      owners.has(at) ||
+      /hidden|clip|auto|scroll/.test(getComputedStyle(at).overflowY)
+    ) {
+      const clip = at.getBoundingClientRect()
+      top = Math.max(top, clip.top)
+      bottom = Math.min(bottom, clip.bottom)
+    }
+  }
+  return box.bottom > top && box.top < bottom
+}
+
+export function mobileNativeChatReadingParts(root: Element): Element[] {
+  const parts = Array.from(root.querySelectorAll(`[data-testid^="chat-member:"], [${ROOT}]`))
+  return Array.from(
+    new Set(parts.map((part) => mobileNativeChatScrollFrame(part, root) ?? part))
+  ).filter((part) => mobileNativeChatVisible(part, root))
+}
+
+export { owners as mobileNativeChatScrollRootOwners, ROOT as mobileNativeChatScrollRootAttribute }
+
+export function mobileNativeChatScrollRootMember(
+  root: Root,
+  position = root.position
+): Element | undefined {
+  return position?.member
+    ? Array.from(root.node.querySelectorAll('[data-testid]')).find(
+        (part) =>
+          part.getAttribute('data-testid') === position.member &&
+          !mobileNativeChatScrollFrame(part, root.node)
+      )
+    : undefined
+}
+
+export function mobileNativeChatScrollRootShift(root: Root): number {
+  const position = root.position
+  const member = mobileNativeChatScrollRootMember(root, position)
+  return member && position?.offset !== undefined
+    ? member.getBoundingClientRect().top -
+        root.node.getBoundingClientRect().top -
+        position.offset +
+        root.node.scrollTop -
+        position.top
+    : 0
+}
+
+export function mobileNativeChatRootsDeepestFirst(roots: Iterable<Root>) {
+  return Array.from(roots)
+    .map((root, index) => {
+      let depth = 0
+      for (let node = root.node.parentElement; node; node = node.parentElement) {
+        depth += 1
+      }
+      return { root, depth, index }
+    })
+    .sort((a, b) => b.depth - a.depth || a.index - b.index)
+}
diff --git a/mobile/src/session/mobile-native-chat-scroll-roots.ts b/mobile/src/session/mobile-native-chat-scroll-roots.ts
new file mode 100644
index 00000000000..dd20ca245e3
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-scroll-roots.ts
@@ -0,0 +1,318 @@
+import { MobileNativeChatPageMotion, pageKeepsPlace } from './mobile-native-chat-page-motion'
+import { MobileNativeChatPageAnchoring } from './mobile-native-chat-page-anchoring'
+import {
+  mobileNativeChatScrollRootAttribute as ROOT,
+  mobileNativeChatScrollRootOwners as owners,
+  mobileNativeChatScrollRootMember as rootMember,
+  mobileNativeChatScrollRootShift as shift,
+  mobileNativeChatReadingParts,
+  mobileNativeChatRootsDeepestFirst,
+  type MobileNativeChatRootPosition,
+  type MobileNativeChatScrollRootHandle as Root
+} from './mobile-native-chat-scroll-root-handle'
+export {
+  mobileNativeChatScrollRootKey,
+  mobileNativeChatScrollFrame,
+  mobileNativeChatVisible,
+  mobileNativeChatReadingParts
+} from './mobile-native-chat-scroll-root-handle'
+export type { MobileNativeChatRootPosition } from './mobile-native-chat-scroll-root-handle'
+
+/** A disclosure owns its own segment anywhere in an address, its `key:part` leaves, and all below. */
+function disclosureOwns(key: string, address: string): boolean {
+  for (let at = address.indexOf(key); at >= 0; at = address.indexOf(key, at + 1)) {
+    const next = address[at + key.length]
+    if (
+      (at === 0 || address[at - 1] === '/') &&
+      (next === undefined || next === '/' || next === ':')
+    ) {
+      return true
+    }
+  }
+  return false
+}
+
+/** Mounted handles only; the chat's existing bounded memory owns positions across eviction. */
+export class MobileNativeChatScrollRoots {
+  private roots = new Map<string, Root>()
+  private observer: ResizeObserver | null = null
+  private held = new Set<Root>()
+  private generation = 0
+  private page: MobileNativeChatPageMotion | null = null
+
+  constructor(
+    private readonly memory: Map<string, MobileNativeChatRootPosition>,
+    private readonly limit: number
+  ) {}
+
+  register(
+    id: string,
+    node: HTMLElement,
+    content: Element,
+    owner: string,
+    address: string,
+    initialFollow: boolean
+  ): () => void {
+    const was = this.roots.get(id)
+    if (was?.node === node && was.content === content && was.owner === owner) {
+      return () => this.unregister(was, true)
+    }
+    if (was) {
+      this.unregister(was, true)
+    }
+    const occupant = owners.get(node)
+    if (occupant) {
+      this.unregister(occupant, true)
+    }
+    const motion = new MobileNativeChatPageMotion(() => {}, node.scrollTop)
+    const root: Root = {
+      id,
+      address,
+      owner,
+      node,
+      content,
+      position: {
+        ...(this.memory.get(address) ?? { top: node.scrollTop, followsEnd: initialFollow })
+      },
+      work: undefined,
+      nextWork: undefined,
+      fresh: true,
+      motion,
+      anchoring: new MobileNativeChatPageAnchoring(
+        () => node,
+        () => root.position.followsEnd
+      ),
+      detach: () => {}
+    }
+    const input = motion.attach(
+      node,
+      (event) =>
+        event instanceof Event && event.target instanceof Node && node.contains(event.target)
+    )
+    const scrolled = () => {
+      const max = node.scrollHeight - node.clientHeight
+      const { by } = motion.scrolled(node.scrollTop, max, () => Math.abs(shift(root)) >= 0.5)
+      if (by === 'reader') {
+        if (root.nextWork !== undefined) {
+          root.position.followsEnd = max - node.scrollTop <= 24
+        }
+        this.remember(root)
+      }
+      root.anchoring.sync()
+    }
+    node.addEventListener('scroll', scrolled, { passive: true })
+    root.detach = () => {
+      input()
+      node.removeEventListener('scroll', scrolled)
+    }
+    owners.set(node, root)
+    node.setAttribute(ROOT, '')
+    this.roots.set(id, root)
+    this.observer?.observe(node)
+    this.observer?.observe(content)
+    this.hold(root)
+    return () => this.unregister(root, true)
+  }
+
+  private unregister(root: Root, remember: boolean): void {
+    const current = this.roots.get(root.id) === root
+    if (current && remember && root.node.isConnected && !this.held.has(root)) {
+      this.remember(root)
+    }
+    root.detach()
+    root.motion.release()
+    for (const target of [root.node, root.content]) {
+      const viewport = owners.get(target)
+      const parent = target.parentElement
+      const container = parent ? owners.get(parent) : undefined
+      if (
+        !(viewport && viewport !== root && this.roots.get(viewport.id) === viewport) &&
+        !(
+          container &&
+          container !== root &&
+          container.content === target &&
+          this.roots.get(container.id) === container
+        )
+      ) {
+        this.observer?.unobserve(target)
+      }
+    }
+    if (owners.get(root.node) === root) {
+      owners.delete(root.node)
+      root.node.removeAttribute(ROOT)
+    }
+    if (current) {
+      this.roots.delete(root.id)
+    }
+    if (this.held.delete(root)) {
+      root.anchoring.hold(false)
+    }
+  }
+
+  readonly observeWith = (observer: ResizeObserver | null): void => {
+    for (const { node, content } of this.roots.values()) {
+      this.observer?.unobserve(node)
+      this.observer?.unobserve(content)
+      observer?.observe(node)
+      observer?.observe(content)
+    }
+    this.observer = observer
+  }
+
+  layout(id: string, address: string, work?: number): void {
+    const root = this.roots.get(id)
+    if (!root) {
+      return
+    }
+    root.address = address
+    root.nextWork = work
+    root.motion.laidOut(`${work}:${root.node.scrollHeight}:${root.node.clientHeight}`)
+  }
+
+  private remember(root: Root): void {
+    const { node, address } = root
+    const member =
+      mobileNativeChatReadingParts(node).find((part) => !owners.has(part)) ?? rootMember(root)
+    root.position = {
+      top: node.scrollTop,
+      followsEnd: root.position.followsEnd,
+      ...(member
+        ? {
+            member: member.getAttribute('data-testid') ?? undefined,
+            offset: member.getBoundingClientRect().top - node.getBoundingClientRect().top
+          }
+        : {})
+    }
+    this.memory.delete(address)
+    this.memory.set(address, { ...root.position })
+    if (this.memory.size > this.limit) {
+      const oldest = this.memory.keys().next().value
+      if (oldest !== undefined) {
+        this.memory.delete(oldest)
+      }
+    }
+  }
+
+  private hold(root: Root): void {
+    if (!this.held.has(root)) {
+      this.held.add(root)
+      root.anchoring.hold(true)
+    }
+  }
+
+  capture(movedOwners: ReadonlySet<string>, regrouped: boolean): void {
+    for (const root of this.roots.values()) {
+      if (!root.fresh) {
+        this.remember(root)
+      }
+      if (regrouped || movedOwners.has(root.owner)) {
+        this.hold(root)
+      }
+    }
+  }
+
+  /** Called by the parent commit boundary and the one shared observer, deepest viewport first. */
+  restoreAll(regrouped = false, release = true): void {
+    const roots = mobileNativeChatRootsDeepestFirst(this.roots.values())
+    try {
+      for (const { root } of roots) {
+        const { node, motion } = root
+        if (!node.isConnected) {
+          continue
+        }
+        const max = Math.max(0, node.scrollHeight - node.clientHeight)
+        const { by } = motion.reconciled(node.scrollTop, max)
+        if (by === 'reader') {
+          if (root.work !== undefined) {
+            root.position.followsEnd = max - node.scrollTop <= 24
+          }
+          this.remember(root)
+        }
+        const position = root.position
+        const pin = position.followsEnd && (root.fresh || root.work !== root.nextWork)
+        const explicit = this.held.has(root)
+        const member = rootMember(root, position)
+        const target = pin
+          ? max
+          : member && position?.offset !== undefined
+            ? node.scrollTop +
+              member.getBoundingClientRect().top -
+              node.getBoundingClientRect().top -
+              position.offset
+            : (position?.top ?? node.scrollTop)
+        const ordinary = !position.followsEnd && pageKeepsPlace(node.scrollTop)
+        const clamped = Math.max(0, Math.min(target, max))
+        if (
+          (pin || explicit || ordinary) &&
+          (regrouped || motion.mayCorrect()) &&
+          node.scrollTop >= 0 &&
+          node.scrollTop <= max + 1 &&
+          Math.abs(clamped - node.scrollTop) >= 0.5
+        ) {
+          node.scrollTop = clamped
+          motion.wrote(node.scrollTop)
+        }
+        root.fresh = false
+        root.work = root.nextWork
+        this.remember(root)
+        root.anchoring.committed()
+      }
+    } finally {
+      if (release) {
+        this.releaseHold()
+      }
+    }
+  }
+
+  releaseHold(): void {
+    for (const root of this.held) {
+      root.anchoring.hold(false)
+    }
+    this.held.clear()
+  }
+
+  frame(key: string): Element | undefined {
+    return this.roots.get(key)?.node
+  }
+  owner(key: string): string | undefined {
+    return this.roots.get(key)?.owner
+  }
+
+  forget(key: string): void {
+    for (const root of this.roots.values()) {
+      if (disclosureOwns(key, root.address)) {
+        this.unregister(root, false)
+      }
+    }
+    for (const child of this.memory.keys()) {
+      if (disclosureOwns(key, child)) {
+        this.memory.delete(child)
+      }
+    }
+  }
+
+  async settled(page: MobileNativeChatPageMotion): Promise<void> {
+    const generation = this.generation
+    this.page = page
+    do {
+      await Promise.all([
+        page.whenSettled(),
+        ...Array.from(this.roots.values(), (r) => r.motion.whenSettled())
+      ])
+      if (generation !== this.generation) {
+        return
+      }
+    } while (!page.settled() || Array.from(this.roots.values()).some((r) => !r.motion.settled()))
+  }
+
+  dispose(): void {
+    this.generation += 1
+    for (const root of this.roots.values()) {
+      this.unregister(root, false)
+    }
+    this.page?.release()
+    this.page = null
+    this.observer = null
+    this.releaseHold()
+  }
+}
diff --git a/mobile/src/session/mobile-native-chat-tool-run-props.ts b/mobile/src/session/mobile-native-chat-tool-run-props.ts
new file mode 100644
index 00000000000..2a737d078ae
--- /dev/null
+++ b/mobile/src/session/mobile-native-chat-tool-run-props.ts
@@ -0,0 +1,34 @@
+import type {
+  NativeChatBlock,
+  NativeChatToolCallBlock
+} from '../../../src/shared/native-chat-types'
+
+/** Desktop parity: `NativeChatToolRunAsides`. Rows drawn among an open run's lines, each keyed:
+ *  before the block they are keyed by, or after the last. */
+export type MobileNativeChatToolRunAsides = {
+  before: ReadonlyMap<NativeChatBlock, readonly React.JSX.Element[]>
+  after: readonly React.JSX.Element[]
+}
+
+export type MobileNativeChatToolRunProps = {
+  blocks: NativeChatBlock[]
+  /** The last plan each task-list tool wrote before this run, so an update reads as its changes. */
+  previousTodoWrite?: NativeChatToolCallBlock
+  previousUpdatePlan?: NativeChatToolCallBlock
+  defaultExpanded: boolean
+  /** The row this run belongs to. The list recycles rows, so what the reader opened is
+   *  remembered somewhere that outlives the row. */
+  disclosureId?: string
+  /** Rows drawn among the run's lines, each before the block it is keyed by, or after the last. */
+  asides?: MobileNativeChatToolRunAsides
+  /** Every line's default: open under the Tools toggle. */
+  expandChildren: boolean
+  /** Structured lifecycle state; keeps an orphaned running call from spinning. */
+  activeTurnIsWorking?: boolean
+  /** Whether this run is the working turn's last. Only that run is live. */
+  trailing?: boolean
+  /** The turn is blocked on the reader's answer, so its calls decide liveness. */
+  awaitingAnswer?: boolean
+  fontScale?: number
+  onOpenFile?: (path: string) => void
+}
diff --git a/mobile/src/session/mobile-native-chat-view-styles.ts b/mobile/src/session/mobile-native-chat-view-styles.ts
index 8d35da5d00e..8984d682e75 100644
--- a/mobile/src/session/mobile-native-chat-view-styles.ts
+++ b/mobile/src/session/mobile-native-chat-view-styles.ts
@@ -98,5 +98,11 @@ export const styles = StyleSheet.create({
     color: colors.textMuted,
     fontSize: typography.metaSize,
     fontWeight: '600'
+  },
+  loadEarlierFailedText: {
+    color: colors.textMuted,
+    fontSize: typography.metaSize,
+    textAlign: 'center',
+    marginTop: spacing.xs
   }
 })
diff --git a/mobile/src/session/mobile-session-read-operations.ts b/mobile/src/session/mobile-session-read-operations.ts
index 3e75554fd1e..2fac18b2ac0 100644
--- a/mobile/src/session/mobile-session-read-operations.ts
+++ b/mobile/src/session/mobile-session-read-operations.ts
@@ -143,9 +143,9 @@ export const nativeChatFileInventoryRead = bindDeferredRpcOperation(
 /**
  * The older-history page native chat asks for when the transcript is scrolled back.
  *
- * A skip rather than a throw: a refused page leaves the window the subscription already delivered
- * and the scroll simply does not grow, which is what the call site's `if (!response.ok) return`
- * did. There is no screen to raise a host message on — the pane is already showing history.
+ * A skip rather than a throw: a refused page leaves the window the subscription already delivered,
+ * and the call site shows its own retry line. The host's message isn't raised; it is an internal
+ * code the reader can't act on.
  *
  * The payload stays whole rather than being narrowed to `messages`, because the reply is a union:
  * an older runtime answers `{ error }` in place of a window, and the caller discriminates on that
diff --git a/mobile/src/session/use-mobile-native-chat-page-history.test.tsx b/mobile/src/session/use-mobile-native-chat-page-history.test.tsx
deleted file mode 100644
index 56080cb4d3d..00000000000
--- a/mobile/src/session/use-mobile-native-chat-page-history.test.tsx
+++ /dev/null
@@ -1,95 +0,0 @@
-import { createElement, type ReactElement } from 'react'
-import { act, create, type ReactTestRenderer } from 'react-test-renderer'
-import { afterEach, describe, expect, it, vi } from 'vitest'
-import { useMobileNativeChatPageHistory } from './use-mobile-native-chat-page-history'
-
-const platform = vi.hoisted(() => ({ OS: 'web' }))
-
-vi.mock('react-native', () => ({ Platform: platform }))
-
-type Item = { id: string }
-type History = ReturnType<typeof useMobileNativeChatPageHistory<Item>>
-
-const rows = (...ids: string[]): Item[] => ids.map((id) => ({ id }))
-const renderRow = vi.fn(({ item, index }: { item: Item; index: number }): ReactElement =>
-  createElement('Row', { id: item.id, index })
-)
-
-describe('useMobileNativeChatPageHistory', () => {
-  let renderer: ReactTestRenderer | null = null
-  let history: History | null = null
-
-  function Harness({ items }: { items: Item[] }): null {
-    history = useMobileNativeChatPageHistory(items, renderRow, 'chat')
-    return null
-  }
-
-  async function show(items: Item[]): Promise<void> {
-    await act(async () => {
-      if (renderer) {
-        renderer.update(createElement(Harness, { items }))
-      } else {
-        renderer = create(createElement(Harness, { items }))
-      }
-    })
-  }
-
-  /** What the list header draws below the control it was given. */
-  function headerRows(): { id: string; index: number }[] {
-    const drawn: { header?: ReactTestRenderer } = {}
-    act(() => {
-      drawn.header = create(
-        createElement('Header', null, history?.withHistory(createElement('Control')))
-      )
-    })
-    const found = drawn.header?.root.findAll((node) => typeof node.props.index === 'number') ?? []
-    return found.map((row) => ({ id: row.props.id, index: row.props.index }))
-  }
-
-  afterEach(() => {
-    act(() => renderer?.unmount())
-    renderer = null
-    history = null
-    platform.OS = 'web'
-  })
-
-  it('draws history that loads above the list in its header, leaving the list its rows', async () => {
-    await show(rows('a', 'b'))
-    expect(history?.listRows).toEqual(rows('a', 'b'))
-    expect(headerRows()).toEqual([])
-
-    await show(rows('x', 'y', 'a', 'b'))
-
-    // RN Web's list draws by index: handing it the new rows would redraw a different set.
-    expect(history?.listRows).toEqual(rows('a', 'b'))
-    expect(headerRows()).toEqual([
-      { id: 'x', index: 0 },
-      { id: 'y', index: 1 }
-    ])
-    // The list's first row is the third row of the chat, and is drawn as that.
-    history?.renderListRow({ item: { id: 'a' }, index: 0 })
-    expect(renderRow).toHaveBeenLastCalledWith({ item: { id: 'a' }, index: 2 })
-  })
-
-  it('gives the list every row again once the row it started at is gone', async () => {
-    await show(rows('a', 'b'))
-    await show(rows('x', 'a', 'b'))
-
-    await show(rows('p', 'q'))
-
-    expect(history?.listRows).toEqual(rows('p', 'q'))
-    expect(headerRows()).toEqual([])
-  })
-
-  it('leaves a native list all its rows: it holds its own place', async () => {
-    platform.OS = 'ios'
-    await show(rows('a', 'b'))
-    const all = rows('x', 'y', 'a', 'b')
-
-    await show(all)
-
-    expect(history?.listRows).toBe(all)
-    expect(history?.renderListRow).toBe(renderRow)
-    expect(headerRows()).toEqual([])
-  })
-})
diff --git a/mobile/src/session/use-mobile-native-chat-page-history.tsx b/mobile/src/session/use-mobile-native-chat-page-history.tsx
deleted file mode 100644
index e1102161d99..00000000000
--- a/mobile/src/session/use-mobile-native-chat-page-history.tsx
+++ /dev/null
@@ -1,66 +0,0 @@
-import { Fragment, useCallback, useMemo, useState, type ReactElement } from 'react'
-import { Platform } from 'react-native'
-
-const NO_ROWS: readonly never[] = []
-
-type Row<TItem> = { item: TItem; index: number }
-
-/** RN Web's list draws rows by index, so rows added at the front push the ones a reader is on out
- *  of what it draws. On the page, rows that arrive above the list's first row go in its header
- *  instead: the list's own rows keep their indexes and stay drawn. */
-export function useMobileNativeChatPageHistory<TItem extends { id: string }>(
-  rows: readonly TItem[],
-  renderRow: (row: Row<TItem>) => ReactElement,
-  /** The chat shown: synthetic row ids (the streaming bubble, an echo) repeat across chats. */
-  scopeKey: string
-): {
-  listRows: readonly TItem[]
-  renderListRow: (row: Row<TItem>) => ReactElement
-  /** The list header: what was given, then the history loaded above the list's own rows. */
-  withHistory: (header: ReactElement | null) => ReactElement | null
-} {
-  const onPage = Platform.OS === 'web'
-  // The row the list starts at, for as long as that row exists in this chat.
-  const [head, setHead] = useState<{ scopeKey: string; id: string } | null>(null)
-  const headId = head?.scopeKey === scopeKey ? head.id : null
-  const headIndex = useMemo(
-    () => (onPage && headId !== null ? rows.findIndex((row) => row.id === headId) : -1),
-    [onPage, headId, rows]
-  )
-  const firstId = rows[0]?.id
-  if (onPage && headIndex === -1 && firstId !== undefined && firstId !== headId) {
-    setHead({ scopeKey, id: firstId })
-  }
-  const historyCount = Math.max(headIndex, 0)
-  const historyRows = useMemo(
-    () => (historyCount === 0 ? NO_ROWS : rows.slice(0, historyCount)),
-    [historyCount, rows]
-  )
-  const listRows = useMemo(
-    () => (historyCount === 0 ? rows : rows.slice(historyCount)),
-    [historyCount, rows]
-  )
-  const renderOffsetRow = useCallback(
-    (row: Row<TItem>) => renderRow({ item: row.item, index: row.index + historyCount }),
-    [renderRow, historyCount]
-  )
-  const withHistory = useCallback(
-    (header: ReactElement | null) =>
-      historyRows.length === 0 ? (
-        header
-      ) : (
-        <>
-          {header}
-          {historyRows.map((item, index) => (
-            <Fragment key={item.id}>{renderRow({ item, index })}</Fragment>
-          ))}
-        </>
-      ),
-    [historyRows, renderRow]
-  )
-  return {
-    listRows,
-    renderListRow: historyCount === 0 ? renderRow : renderOffsetRow,
-    withHistory
-  }
-}
diff --git a/mobile/src/session/use-mobile-native-chat-page-render.ts b/mobile/src/session/use-mobile-native-chat-page-render.ts
new file mode 100644
index 00000000000..ea46c77b649
--- /dev/null
+++ b/mobile/src/session/use-mobile-native-chat-page-render.ts
@@ -0,0 +1,18 @@
+import { useCallback, useRef, useSyncExternalStore } from 'react'
+
+/** Renders the caller again from any event source (a scroll, the observer, a timer) synchronously,
+ *  so a window change is in the document before the browser paints. */
+export function useMobileNativeChatPageRender(): () => void {
+  const store = useRef({ version: 0, notify: () => {} })
+  const subscribe = useCallback((notify: () => void) => {
+    store.current.notify = notify
+    return () => {
+      store.current.notify = () => {}
+    }
+  }, [])
+  useSyncExternalStore(subscribe, () => store.current.version)
+  return useCallback(() => {
+    store.current.version += 1
+    store.current.notify()
+  }, [])
+}
diff --git a/mobile/src/session/use-mobile-native-chat-page-window.ts b/mobile/src/session/use-mobile-native-chat-page-window.ts
new file mode 100644
index 00000000000..d07064e7e29
--- /dev/null
+++ b/mobile/src/session/use-mobile-native-chat-page-window.ts
@@ -0,0 +1,342 @@
+import { useCallback, useLayoutEffect, useMemo, useRef, useState } from 'react'
+import { MobileNativeChatPageHeights } from './mobile-native-chat-page-heights'
+import { MobileNativeChatPageAnchoring } from './mobile-native-chat-page-anchoring'
+import {
+  MobileNativeChatPageMotion,
+  pageKeepsPlace,
+  scrollWritesStopMomentum
+} from './mobile-native-chat-page-motion'
+import { MobileNativeChatPageRows } from './mobile-native-chat-page-rows'
+import { coverMobileNativeChatWindow } from './mobile-native-chat-page-window-coverage'
+import type {
+  MobileNativeChatWindowDrawn as Drawn,
+  MobileNativeChatWindowGroup as Group,
+  MobileNativeChatPageWindowArgs,
+  MobileNativeChatWindowScroller,
+  MobileNativeChatWindowSeat as Win
+} from './mobile-native-chat-page-window-state'
+import { useMobileNativeChatPageRender } from './use-mobile-native-chat-page-render'
+
+/** Rows measured in one settled moment: few enough not to drop a frame. */
+const MEASURE_ROWS = 8
+/** Between measuring rounds, so a streamed reply still gets frames while rows are measured. */
+const MEASURE_GAP_MS = 32
+/** A parked reader's unmeasured rows are measured only within this many screens above them. */
+const MEASURE_REACH = 3
+/** While following, every measured row is checked for a change at most this often. */
+const STALE_SCAN_MS = 1_000
+/** While following, measuring waits until a streaming reply pauses this long, so its updates keep
+ *  the frames. */
+const STREAM_PAUSE_MS = 300
+
+/** The page's rows near the screen, keyed. Above the window the spacer stands only for measured rows:
+ *  rows never measured are left out, and are measured in place only while nothing can move the
+ *  reader (following, or settled), because iOS stops momentum on any scroll write. */
+export function useMobileNativeChatPageWindow(args: MobileNativeChatPageWindowArgs) {
+  const { rows, rowKeys, rowState, following, isFollowing, layoutKey, scroller, roots } = args
+  const render = useMobileNativeChatPageRender()
+  const [heights] = useState(() => new MobileNativeChatPageHeights())
+  const w = useRef<Win | null>(null)
+  const drawn = useRef<Drawn | null>(null)
+  const settle = useRef(false)
+  const [drawnRows] = useState(() => new MobileNativeChatPageRows())
+  const anchorStale = useRef(false)
+  const width = useRef(0)
+  const viewport = useRef(globalThis.innerHeight || 800)
+  const lastScan = useRef(0)
+  const streamedAt = useRef(0)
+  const onSettled = useRef(() => {})
+  const [motion] = useState(() => new MobileNativeChatPageMotion(() => onSettled.current()))
+  const [anchoring] = useState(() => new MobileNativeChatPageAnchoring(scroller, isFollowing))
+  const { keys, changed, indexOf } = useMemo(
+    () => heights.sourceKeys(rows, rowKeys.keyOf, drawn.current?.keys),
+    [rows, rowKeys.keyOf, heights]
+  )
+  const n = keys.length
+  const at = (key: string, fallback: number): number =>
+    keys[fallback] === key
+      ? fallback
+      : (indexOf(rowKeys.current(key)) ?? Math.max(0, Math.min(fallback, n - 1)))
+  const seatAtEnd = (): Win => {
+    let first = n
+    for (let filled = 0; first > 0 && filled < viewport.current; first -= 1) {
+      filled += heights.px(keys[first - 1]) ?? heights.estimate()
+    }
+    const seat = { first: keys[first] ?? '', firstAt: first, last: null, lastAt: n - 1 }
+    return { scope: rowKeys.scope, ...seat, slack: 0, measure: null }
+  }
+
+  const kept = w.current?.scope === rowKeys.scope && w.current.first !== '' ? w.current : null
+  let win = kept ?? seatAtEnd()
+  let end = win.last === null ? n : at(win.last, win.lastAt) + 1
+  if (following && win.last !== null) {
+    win = end >= n ? { ...win, last: null } : seatAtEnd()
+    end = n
+  }
+  const start = Math.min(at(win.first, win.firstAt), Math.max(0, end - 1))
+  end = Math.min(n, Math.max(end, start + 1))
+
+  const d = drawn.current
+  const sourceChanged = d !== null && d.sourceHead !== rowKeys.sourceHead
+  let slack = following || !kept || settle.current ? 0 : win.slack
+  if (d && sourceChanged && !following && kept && d.keys !== keys) {
+    // A cap trim takes rows from the top; what was drawn of them stays as space until settled.
+    for (let i = d.first; i < d.end && indexOf(rowKeys.current(d.keys[i]!)) === undefined; i += 1) {
+      slack += heights.px(d.keys[i]) ?? 0
+    }
+  }
+  // A source change keeps no measuring rows: the place-hold owns that commit's correction.
+  let [m0, m1] = [start, start]
+  const group = sourceChanged || !win.measure ? null : win.measure
+  if (group) {
+    const [from, to] = [at(group.from, group.fromAt), at(group.to, group.toAt) + 1]
+    if (from < to && to <= start) {
+      ;[m0, m1] = [from, to]
+    }
+  }
+  const { first, above, mid, bottom } = heights.spacers(keys, [m0, m1], [start, end], slack)
+  const measuring = n > 0 && Math.min(m0, start) > 0 && heights.px(keys[0]) === undefined
+
+  const write = useCallback(
+    (s: MobileNativeChatWindowScroller, to: number) => {
+      const max = s.scrollHeight - s.clientHeight
+      const target = Math.max(0, Math.min(to, max))
+      // Above the top only while iOS bounces there. Past the end may be a clamp the browser hasn't
+      // applied yet; every write here waits for rest, so it isn't a bounce.
+      if (s.scrollTop >= 0 && Math.abs(target - s.scrollTop) >= 0.5) {
+        motion.wrote(target)
+        s.scrollTop = target
+      }
+    },
+    [motion]
+  )
+
+  const takeAnchor = useCallback(
+    (s: MobileNativeChatWindowScroller) => {
+      // Elsewhere the browser's anchoring keeps a parked place and the end pin a following one.
+      if (!pageKeepsPlace(s.scrollTop)) {
+        drawnRows.forgetAnchor()
+        return
+      }
+      const at = drawn.current
+      // A following reader is held by the end pin: the row's own top is enough there.
+      drawnRows.takeAnchor(s, at?.keys ?? [], [at?.start ?? 0, at?.end ?? 0], !at?.following)
+    },
+    [drawnRows]
+  )
+
+  const cover = useCallback(
+    (s: MobileNativeChatWindowScroller) => {
+      const [at, cur] = [drawn.current, w.current]
+      const firstNode = at && drawnRows.node(at.keys[at.start])
+      // Before the observer reports every drawn row, a guess would move the window off the reader.
+      const unmeasured =
+        at && at.keys.slice(at.start, at.end).some((key) => heights.px(key) === undefined)
+      if (!at || !cur || !firstNode || unmeasured) {
+        return
+      }
+      const next = coverMobileNativeChatWindow(
+        {
+          n: at.keys.length,
+          start: at.start,
+          end: at.end,
+          // Drawn to the end only while it is near: a jump away is drawn where it lands, not to the end.
+          following: at.following && s.scrollTop >= s.scrollHeight - 2 * s.clientHeight,
+          windowTop:
+            firstNode.getBoundingClientRect().top - s.getBoundingClientRect().top + s.scrollTop,
+          scrollTop: s.scrollTop,
+          viewport: s.clientHeight
+        },
+        (i) => heights.px(at.keys[i]),
+        heights.estimate()
+      )
+      if (next) {
+        const last = next.end >= at.keys.length ? null : at.keys[next.end - 1]!
+        const measure = next.start === at.start ? cur.measure : null
+        const moved = { first: at.keys[next.start]!, firstAt: next.start, last }
+        w.current = { ...cur, ...moved, lastAt: next.end - 1, measure }
+        render()
+      }
+    },
+    [heights, render, drawnRows]
+  )
+
+  // Owed work that can move rows above the reader, done only while settled: measure the nearest rows
+  // that are unmeasured or may have changed, and give back trimmed space.
+  const measureOwed = useCallback(() => {
+    const [at, cur] = [drawn.current, w.current]
+    if (!at || !cur || at.keys.length === 0) {
+      return
+    }
+    const layout = `${at.layoutKey}:${width.current}`
+    // A drawn group is measured before paint; choosing again first would take it down unmeasured.
+    if (cur.measure && heights.px(cur.measure.to) === undefined) {
+      return
+    }
+    const streaming = STREAM_PAUSE_MS - (Date.now() - streamedAt.current)
+    if (at.following && streaming > 0) {
+      motion.pokeIn(streaming)
+      return
+    }
+    const since = Date.now() - lastScan.current
+    const full = at.following && at.first === 0 && since >= STALE_SCAN_MS
+    const run = heights.next(at, layout, MEASURE_REACH * viewport.current, MEASURE_ROWS, full)
+    if (full) {
+      lastScan.current = Date.now()
+    } else if (!run && at.following && at.first === 0) {
+      motion.pokeIn(STALE_SCAN_MS - since)
+    }
+    const measure: Group | null = run && {
+      from: at.keys[run[0]]!,
+      fromAt: run[0],
+      to: at.keys[run[1]]!,
+      toAt: run[1]
+    }
+    if (measure?.from !== cur.measure?.from || measure?.to !== cur.measure?.to || cur.slack > 0) {
+      w.current = { ...cur, measure }
+      settle.current = true
+      motion.quiet(MEASURE_GAP_MS)
+      render()
+    }
+  }, [heights, motion, render])
+
+  useLayoutEffect(() => {
+    onSettled.current = measureOwed
+    if (w.current && w.current.scope !== rowKeys.scope) {
+      heights.clear()
+      motion.release()
+      drawnRows.forgetAnchor()
+    }
+    if (changed && drawn.current?.keys !== keys) {
+      heights.retain(keys)
+    }
+    const last = end >= n ? null : keys[end - 1]!
+    const m = m0 < m1 ? { from: keys[m0]!, fromAt: m0, to: keys[m1 - 1]!, toAt: m1 - 1 } : null
+    const seat = { first: keys[start] ?? '', firstAt: start, last, lastAt: end - 1 }
+    w.current = { ...win, ...seat, slack, measure: m }
+    if (drawn.current && drawn.current.rows !== rows && following) {
+      streamedAt.current = Date.now()
+    }
+    const fresh = { keys, rows, indexOf, rowState, start, end, first, following, layoutKey }
+    drawn.current = { ...fresh, sourceHead: rowKeys.sourceHead }
+    settle.current = false
+    anchoring.committed()
+    const s = scroller()
+    if (s && anchorStale.current) {
+      anchorStale.current = false
+      takeAnchor(s)
+    }
+    motion.laidOut([n, m0, m1, start, end, above, mid, bottom, layoutKey].join(':'))
+    if (n > 0) {
+      motion.poke()
+    }
+  })
+
+  useLayoutEffect(() => {
+    const s = scroller()
+    if (!s) {
+      return
+    }
+    const scrolled = () => {
+      // A write's or layout's event can arrive after rows above changed and before the correction:
+      // taking the place or covering then would keep the moved position and draw what moved it.
+      const max = s.scrollHeight - s.clientHeight
+      const { by } = motion.scrolled(s.scrollTop, max, () => drawnRows.placeMoved(s))
+      if (by === 'reader') {
+        takeAnchor(s)
+      }
+      // Where the browser keeps the place, the page writes no correction to wait for.
+      if (by === 'reader' || (by === 'layout' && !scrollWritesStopMomentum())) {
+        cover(s)
+      }
+    }
+    const detach = motion.attach(s)
+    s.addEventListener('scroll', scrolled, { passive: true })
+    return () => {
+      detach()
+      s.removeEventListener('scroll', scrolled)
+      motion.release()
+    }
+  }, [scroller, motion, takeAnchor, cover, drawnRows, anchoring, roots])
+
+  /** The one observer's entries: rows measured, then, for a parked reader (on WebKit at rest),
+   *  whatever moved the row they were reading goes back (a measured row, the header, given-back
+   *  space). */
+  const afterResize = useCallback(
+    (entries: readonly ResizeObserverEntry[], pin: () => void) => {
+      const [s, at] = [scroller(), drawn.current]
+      if (!s || !at) {
+        return pin()
+      }
+      viewport.current = s.clientHeight
+      width.current = s.clientWidth
+      const layout = `${at.layoutKey}:${width.current}`
+      for (const entry of entries) {
+        const key = drawnRows.keyOf(entry.target)
+        const i = at.indexOf(key)
+        if (key !== undefined && i !== undefined) {
+          const row = at.rows[i]!
+          heights.remember(key, entry.contentRect.height, row, at.rowState(i, row), layout)
+        }
+      }
+      // As of the layout, before a move no scroll event has reported yet is counted.
+      roots?.restoreAll()
+      const own = !at.following && motion.mayCorrect() && pageKeepsPlace(s.scrollTop)
+      const shift = own ? drawnRows.placeShift(s) : null
+      const max = s.scrollHeight - s.clientHeight
+      const { by, moved } = motion.reconciled(s.scrollTop, max)
+      if (shift !== null) {
+        // Rows above moved by `shift`: put that back, keep the reader's own move, undo a clamp.
+        write(s, s.scrollTop - (by === 'layout' ? moved : 0) + shift)
+      }
+      // After the reader's unreported move is counted (it may end following), so the pin can't undo it.
+      pin()
+      // The place is where the reader is now: a correction that couldn't land, or a move while
+      // they scrolled, is not owed later.
+      takeAnchor(s)
+      cover(s)
+      motion.poke()
+    },
+    [scroller, heights, motion, write, cover, drawnRows, takeAnchor, roots]
+  )
+
+  /** The place-hold's correction, when one may be written: on WebKit only at rest (mid-motion the
+   *  reader already saw the move, and putting it back at rest would be a second jump), except a
+   *  regroup, which resizes drawn rows at once and nothing redoes later. */
+  const keepInPlace = useCallback(
+    (drift: number, regrouped: boolean) => {
+      const s = scroller()
+      if (s && !drawn.current?.following && (regrouped || motion.mayCorrect())) {
+        write(s, s.scrollTop + drift)
+        anchorStale.current = true
+      }
+    },
+    [scroller, motion, write]
+  )
+
+  // Stable, so the list's handle (and with it the one observer) is made once.
+  const list = useMemo(
+    () => ({
+      afterResize,
+      keepInPlace,
+      observeWith: (observer: ResizeObserver | null) => {
+        drawnRows.observeWith(observer)
+        roots?.observeWith(observer)
+      },
+      settled: () => roots?.settled(motion) ?? motion.whenSettled(),
+      syncAnchoring: () => anchoring.sync(),
+      holdPlace: (on: boolean) => anchoring.hold(on),
+      watchMotion: (fn: typeof motion.onMotion) => {
+        motion.onMotion = fn
+      },
+      wrote: (target: number) => motion.wrote(target)
+    }),
+    [afterResize, keepInPlace, drawnRows, motion, anchoring, roots]
+  )
+
+  return {
+    view: { m0, m1, start, end, above, mid, bottom, measuring },
+    rowRef: drawnRows.ref,
+    list
+  }
+}
diff --git a/mobile/src/session/use-mobile-native-chat-row-renderer.tsx b/mobile/src/session/use-mobile-native-chat-row-renderer.tsx
index 5618cfa9060..51def9c7ee4 100644
--- a/mobile/src/session/use-mobile-native-chat-row-renderer.tsx
+++ b/mobile/src/session/use-mobile-native-chat-row-renderer.tsx
@@ -10,6 +10,8 @@ import type { useMobileNativeChatTurnDisclosure } from './use-mobile-native-chat
 
 /** Desktop parity: `NativeChatTranscriptRow`'s context. */
 export function useMobileNativeChatRowRenderer({
+  rowKeyOf,
+  runOwners,
   toolsExpanded,
   taskListPredecessors,
   fontScale,
@@ -21,6 +23,9 @@ export function useMobileNativeChatRowRenderer({
   receipts,
   actionablePromptIds
 }: {
+  /** The row's place on the page, kept while older messages join it. */
+  rowKeyOf: (message: NativeChatMessage) => string
+  runOwners: ReadonlyMap<string, string>
   toolsExpanded: boolean
   /** The last plan each task-list tool wrote before each row, by row id. */
   taskListPredecessors: ReadonlyMap<string, NativeChatTaskListPredecessors>
@@ -41,6 +46,7 @@ export function useMobileNativeChatRowRenderer({
     ({ item, index }) => (
       <MobileNativeChatMessage
         message={item}
+        rowKey={rowKeyOf(item)}
         toolsExpanded={toolsExpanded}
         // The calls, not the record: a rebuilt record would defeat the row's memo.
         previousTodoWrite={taskListPredecessors.get(item.id)?.todowrite}
@@ -53,9 +59,12 @@ export function useMobileNativeChatRowRenderer({
         receipt={receipts?.get(item.id)}
         awaiting={isActionableStructuredAgentSessionPrompt(item.id, actionablePromptIds)}
         {...turns.resolveRow(index, item)}
+        runOwner={runOwners.get(item.id)}
       />
     ),
     [
+      rowKeyOf,
+      runOwners,
       toolsExpanded,
       taskListPredecessors,
       fontScale,
diff --git a/mobile/src/session/use-mobile-native-chat-session-tool-result-paging.test.tsx b/mobile/src/session/use-mobile-native-chat-session-tool-result-paging.test.tsx
index f876ee85aa4..5392718155d 100644
--- a/mobile/src/session/use-mobile-native-chat-session-tool-result-paging.test.tsx
+++ b/mobile/src/session/use-mobile-native-chat-session-tool-result-paging.test.tsx
@@ -147,12 +147,16 @@ describe('mobile transcript tool result paging', () => {
         current().loadEarlier()
         await Promise.resolve()
       })
-      expect(sendRequest).toHaveBeenCalledWith('nativeChat.readSession', {
-        agent: 'claude',
-        sessionId: 'remote-session',
-        limit: hasCursor ? 60 : 100,
-        ...(hasCursor ? { beforeOffset: 700 } : {})
-      })
+      expect(sendRequest).toHaveBeenCalledWith(
+        'nativeChat.readSession',
+        {
+          agent: 'claude',
+          sessionId: 'remote-session',
+          limit: hasCursor ? 60 : 100,
+          ...(hasCursor ? { beforeOffset: 700 } : {})
+        },
+        expect.objectContaining({ budgetSpansConnect: true })
+      )
       expect(current().messages.map((row) => row.id)).toEqual([
         'prompt',
         'older-calls',
diff --git a/mobile/src/session/use-mobile-native-chat-session.test.ts b/mobile/src/session/use-mobile-native-chat-session.test.ts
index 19ff76a6df8..da787a91d4a 100644
--- a/mobile/src/session/use-mobile-native-chat-session.test.ts
+++ b/mobile/src/session/use-mobile-native-chat-session.test.ts
@@ -3,6 +3,7 @@ import { act, create, type ReactTestRenderer } from 'react-test-renderer'
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
 import type { RpcClient } from '../transport/rpc-client'
+import { createFakeRpcClient, rpcSuccess } from '../mobile-web-shell/bridge-host-test-fakes'
 import {
   useMobileNativeChatSession,
   type MobileNativeChatSession
@@ -49,6 +50,36 @@ describe('useMobileNativeChatSession', () => {
     })
   }
 
+  it.each([true, false])(
+    'preserves only post-response live changes while history waits (overlap: %s)',
+    async (overlap) => {
+      const cached = message('cached')
+      const partial = message('reply')
+      const history = { ...cached, blocks: [{ type: 'text' as const, text: 'fresh history' }] }
+      const final = { ...partial, blocks: [{ type: 'text' as const, text: 'complete' }] }
+      const response = [message('older'), history, partial, ...(overlap ? [] : [message('absent')])]
+      const subscribe: RpcClient['subscribe'] = (_method, _params, onData) => {
+        emit = onData
+        onData({ type: 'snapshot', messages: [cached, partial], hasMore: true })
+        return () => {}
+      }
+      const sendRequest = async () => rpcSuccess('older', { messages: response })
+      let land = () => {}
+      const settled = new Promise<void>((resolve) => {
+        land = resolve
+      })
+      await mount({ ...createFakeRpcClient(), subscribe, sendRequest })
+      await act(async () => {
+        state?.loadEarlier(() => settled)
+      })
+      await act(async () => emit({ type: 'appended', messages: [final, message('suffix')] }))
+      await act(async () => land())
+      expect(state?.messages.find((m) => m.id === 'reply')).toEqual(final)
+      expect(state?.messages.find((m) => m.id === 'cached')).toEqual(history)
+      expect(state?.messages.map((m) => m.id)).toEqual(response.map((m) => m.id).concat('suffix'))
+    }
+  )
+
   it('drops an older-page response captured before transcript replacement', async () => {
     let resolveEarlier: (response: unknown) => void = () => {}
     const sendRequest = vi.fn(
@@ -157,12 +188,11 @@ describe('useMobileNativeChatSession', () => {
       })
 
       expect(sendRequest).toHaveBeenCalledTimes(requestsAtCap + 1)
-      expect(sendRequest).toHaveBeenLastCalledWith('nativeChat.readSession', {
-        agent: 'claude',
-        sessionId: 'session',
-        limit: 60,
-        beforeOffset: 500
-      })
+      expect(sendRequest).toHaveBeenLastCalledWith(
+        'nativeChat.readSession',
+        { agent: 'claude', sessionId: 'session', limit: 60, beforeOffset: 500 },
+        expect.objectContaining({ budgetSpansConnect: true })
+      )
     }
   )
 
@@ -293,11 +323,11 @@ describe('useMobileNativeChatSession', () => {
     )
     act(() => state?.loadEarlier())
 
-    expect(sendRequest).toHaveBeenCalledWith('nativeChat.readSession', {
-      agent: 'claude',
-      sessionId: 'session',
-      limit: 100
-    })
+    expect(sendRequest).toHaveBeenCalledWith(
+      'nativeChat.readSession',
+      { agent: 'claude', sessionId: 'session', limit: 100 },
+      expect.objectContaining({ budgetSpansConnect: true })
+    )
   })
 
   it('clears hasMore when a replaced window is shorter than the initial page', async () => {
@@ -354,6 +384,44 @@ describe('useMobileNativeChatSession', () => {
     expect(state?.loadingEarlier).toBe(false)
   })
 
+  it('lands a page across a same-cursor replay, and flags a refused page until the next tap', async () => {
+    const pages: ((response: unknown) => void)[] = []
+    const sendRequest = vi.fn(() => new Promise((resolve) => pages.push(resolve)))
+    const window = Array.from({ length: 40 }, (_unused, index) => message(`win-${index}`))
+    const snapshot = { type: 'snapshot', messages: window, hasMore: true, beforeOffset: 100 }
+    const subscribe: RpcClient['subscribe'] = vi.fn((_method, _params, onData) => {
+      emit = onData
+      onData(snapshot)
+      return () => {}
+    })
+    await mount({ sendRequest, subscribe } as unknown as RpcClient)
+    const answer = (response: unknown) =>
+      act(async () => {
+        pages.at(-1)?.(response)
+        await Promise.resolve()
+      })
+
+    // A reconnect re-subscribes and replays the same newest window while the page is out.
+    act(() => state?.loadEarlier())
+    await act(async () => emit(snapshot))
+    await answer({
+      ok: true,
+      result: { messages: [message('older')], hasMore: true, beforeOffset: 40 }
+    })
+    expect(state?.messages.map((entry) => entry.id)).toEqual([
+      'older',
+      ...window.map((entry) => entry.id)
+    ])
+
+    act(() => state?.loadEarlier())
+    await answer({ id: 'x', ok: false, error: { code: 'refused', message: 'refused' } })
+    expect(state?.olderPages).toBe('failed')
+    expect(state?.loadingEarlier).toBe(false)
+    act(() => state?.loadEarlier())
+    expect(sendRequest).toHaveBeenCalledTimes(3)
+    expect(state?.olderPages).toBe('loading')
+  })
+
   it('keeps the base snapshot authoritative when a live append arrives first', async () => {
     const sendRequest = vi.fn()
     const subscribe: RpcClient['subscribe'] = vi.fn((_method, _params, onData) => {
@@ -432,11 +500,11 @@ describe('useMobileNativeChatSession', () => {
     act(() => state?.loadEarlier())
 
     // 70 rows held plus one page: a read of 100 would come back shorter than the list it replaces.
-    expect(sendRequest).toHaveBeenLastCalledWith('nativeChat.readSession', {
-      agent: 'claude',
-      sessionId: 'session',
-      limit: 130
-    })
+    expect(sendRequest).toHaveBeenLastCalledWith(
+      'nativeChat.readSession',
+      { agent: 'claude', sessionId: 'session', limit: 130 },
+      expect.objectContaining({ budgetSpansConnect: true })
+    )
   })
 })
 
diff --git a/mobile/src/session/use-mobile-native-chat-session.ts b/mobile/src/session/use-mobile-native-chat-session.ts
index f0017a99ae1..e1936514b4d 100644
--- a/mobile/src/session/use-mobile-native-chat-session.ts
+++ b/mobile/src/session/use-mobile-native-chat-session.ts
@@ -3,7 +3,11 @@ import {
   createNativeChatTranscriptRetention,
   encodeNativeChatTranscriptIdentity
 } from '../../../src/shared/native-chat-transcript-retention'
-import { createNativeChatMerger, replaceList } from '../../../src/shared/native-chat-merge'
+import {
+  createNativeChatMerger,
+  mergeNativeChatMessages,
+  replaceList
+} from '../../../src/shared/native-chat-merge'
 import type { NativeChatMessage } from '../../../src/shared/native-chat-types'
 import { buildNativeChatSubscriptionId } from '../../../src/shared/native-chat-stream-unsubscribe'
 import type { RpcClient } from '../transport/rpc-client'
@@ -13,6 +17,7 @@ import {
   type MobileNativeChatStreamFrame
 } from './mobile-native-chat-stream-frame'
 import { randomV4Uuid } from '../platform/random-v4-uuid'
+import { useMobileOlderPageLoader, type OlderPagePhase } from './use-mobile-older-page-loader'
 
 export type MobileNativeChatStatus =
   | 'idle'
@@ -40,10 +45,13 @@ export type MobileNativeChatSession = {
   readFailedFinally?: boolean
   /** True when an older page may exist (the last read filled the window). */
   hasMore: boolean
-  /** Whether an older-history page is currently loading. */
+  /** `olderPages === 'loading'`, kept because recorded RPC fixtures read it. */
   loadingEarlier: boolean
+  /** The Load earlier control's state: reading now, or how the last read ended. */
+  olderPages?: OlderPagePhase
   /** Grow the window to page in older history. */
-  loadEarlier: () => void
+  /** `settled`: the page waits for it before it lands (the phone page, until the reader stops). */
+  loadEarlier: (settled?: () => Promise<void>) => void
 }
 
 // Small first page for a fast first paint; grows by a page as the user scrolls.
@@ -51,6 +59,17 @@ const INITIAL_LIMIT = 40
 const PAGE = 60
 const MAX_MESSAGES = 2000
 
+/** The next older page, or null once the window holds the most it may. */
+function nextPageWindow(
+  limit: number,
+  listLength: number
+): { nextLimit: number; pageLimit: number } | null {
+  // Live output grows the list past the last read, so the next page counts from what is held.
+  const held = Math.max(limit, listLength)
+  const nextLimit = Math.min(held + PAGE, MAX_MESSAGES)
+  return nextLimit > held ? { nextLimit, pageLimit: nextLimit - held } : null
+}
+
 type ReadSessionResult =
   | { messages: NativeChatMessage[]; hasMore?: boolean; beforeOffset?: number }
   | { error: string }
@@ -102,8 +121,7 @@ export function useMobileNativeChatSession(args: {
   const status = settled ? settled.status : initialStatus
   const [error, setError] = useState<string | undefined>(undefined)
   const [hasMore, setHasMore] = useState(false)
-  const [loadingEarlier, setLoadingEarlier] = useState(false)
-  const loadingEarlierRef = useRef(false)
+  const { phase: olderPages, load: loadOlderPages, supersede } = useMobileOlderPageLoader()
   const beforeOffsetRef = useRef<number | null>(null)
   // Stateful id-dedup merger: caches the id→index map so each live append frame
   // costs O(incoming), not O(existing+incoming) (#18). `replaceList` resets the
@@ -113,7 +131,6 @@ export function useMobileNativeChatSession(args: {
   // Tracks the live session so a late loadEarlier resolve can detect a swap.
   const sessionIdRef = useRef<string | null>(sessionId)
   sessionIdRef.current = sessionId
-  const streamGenerationRef = useRef(0)
   // Whether this subscription already delivered its base snapshot; later
   // snapshots on the same subscription are reconnect replays, not fresh bases.
   const snapshotSeenRef = useRef(false)
@@ -136,11 +153,9 @@ export function useMobileNativeChatSession(args: {
     let cancelled = false
     // Why: disconnect/agent/session loss must invalidate a page request before
     // the early idle/waiting return can clear the visible source.
-    streamGenerationRef.current += 1
+    supersede()
     limitRef.current = INITIAL_LIMIT
-    loadingEarlierRef.current = false
     snapshotSeenRef.current = false
-    setLoadingEarlier(false)
     setList([])
     setError(undefined)
     setHasMore(false)
@@ -188,12 +203,14 @@ export function useMobileNativeChatSession(args: {
           // follows is still this subscription's base, not a reconnect replay.
           snapshotSeenRef.current = true
         }
-        if (applied.windowReplaced || frame.type === 'snapshot') {
-          // Why: any authoritative window (and any replay merge) invalidates an
-          // in-flight older-page request; stale results must not land on it.
-          streamGenerationRef.current += 1
-          loadingEarlierRef.current = false
-          setLoadingEarlier(false)
+        if (
+          applied.windowReplaced ||
+          (frame.type === 'snapshot' && beforeOffsetRef.current === null)
+        ) {
+          // Why: a replaced window fences an in-flight older page, and any replay fences a
+          // cursorless page, which replaces the list. A cursor page survives a contiguous
+          // replay; one that re-cut the cursor fails the page's own cursor check.
+          supersede()
         }
         if (applied.windowReplaced) {
           // Only a genuinely fresh window resets the grown read window — an
@@ -212,9 +229,7 @@ export function useMobileNativeChatSession(args: {
         if (applied.cursorInvalidated) {
           // Fall back to a growing-tail read so history trimmed by live appends
           // cannot leave a gap between the retained window and the old cursor.
-          streamGenerationRef.current += 1
-          loadingEarlierRef.current = false
-          setLoadingEarlier(false)
+          supersede()
           beforeOffsetRef.current = null
         }
         setRead({ client, identity, status: applied.pending ? 'awaiting-transcript' : 'ready' })
@@ -223,89 +238,92 @@ export function useMobileNativeChatSession(args: {
 
     return () => {
       cancelled = true
+      supersede()
       unsubscribe()
     }
-  }, [client, agent, sessionId, transcriptPath, identity, setList])
+  }, [client, agent, sessionId, transcriptPath, identity, setList, supersede])
 
-  const loadEarlier = useCallback(() => {
-    if (!client || !agent || !sessionId || loadingEarlierRef.current || !hasMore) {
-      return
-    }
-    // Capture the session this page belongs to; a swap underneath us must not
-    // apply this read's result onto the new session (mirrors desktop's guard).
-    const requestSessionId = sessionId
-    const requestGeneration = streamGenerationRef.current
-    // Live output grows the list past the last read, so the next page counts from what is held.
-    const held = Math.max(limitRef.current, mergerRef.current.list.length)
-    const nextLimit = Math.min(held + PAGE, MAX_MESSAGES)
-    const pageLimit = nextLimit - held
-    if (pageLimit <= 0) {
-      setHasMore(false)
-      return
-    }
-    const beforeOffset = beforeOffsetRef.current
-    loadingEarlierRef.current = true
-    setLoadingEarlier(true)
-    void (async () => {
-      try {
-        const response = await nativeChatSessionPageRead.request(client, {
-          agent,
-          sessionId,
-          limit: beforeOffset === null ? nextLimit : pageLimit,
-          ...(beforeOffset === null ? {} : { beforeOffset }),
-          ...(transcriptPath ? { transcriptPath } : {})
-        })
+  const loadEarlier = useCallback(
+    (settled?: () => Promise<void>) => {
+      if (!client || !agent || !sessionId || !hasMore) {
+        return
+      }
+      // Capture the session this page belongs to; a swap underneath us must not
+      // apply this read's result onto the new session (mirrors desktop's guard).
+      const requestSessionId = sessionId
+      loadOlderPages(async ({ timeoutMs, isCurrent }) => {
+        const page = nextPageWindow(limitRef.current, mergerRef.current.list.length)
+        if (!page) {
+          setHasMore(false)
+          return 'end'
+        }
+        const { nextLimit, pageLimit } = page
+        const beforeOffset = beforeOffsetRef.current
+        const response = await nativeChatSessionPageRead.request(
+          client,
+          {
+            agent,
+            sessionId,
+            limit: beforeOffset === null ? nextLimit : pageLimit,
+            ...(beforeOffset === null ? {} : { beforeOffset }),
+            ...(transcriptPath ? { transcriptPath } : {})
+          },
+          { timeoutMs, budgetSpansConnect: true }
+        )
         const accepted = nativeChatSessionPageRead.interpret(response)
         if (!accepted.accepted) {
-          return
+          return 'failed'
         }
         // The read is `z.unknown()` because the reply is a union, so an accepted success can still
         // carry no result at all, or null; `'error' in` throws on either.
         const payload = accepted.value
         if (payload === null || typeof payload !== 'object') {
-          return
+          return 'failed'
         }
         // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: main cast this payload unread; the reader hands back the same result.
         const result = payload as ReadSessionResult
         if ('error' in result) {
-          return
+          return 'failed'
         }
-        // Drop a stale resolve from a session that swapped underneath us.
+        const receivedLive = new Map(mergerRef.current.list.map((message) => [message.id, message]))
+        // The page lands once the reader stops scrolling: rows growing above them mid-fling would move
+        // what they read, and iOS stops the fling on the write that would hold it.
+        if (settled) {
+          await settled()
+        }
+        // Lands only on the window and cursor it was asked from; otherwise the window it
+        // read against is gone, and the reader pages again from the new one.
         if (
+          !isCurrent() ||
           sessionIdRef.current !== requestSessionId ||
-          streamGenerationRef.current !== requestGeneration
+          beforeOffsetRef.current !== beforeOffset
         ) {
-          return
+          return 'end'
         }
         limitRef.current = nextLimit
+        let more: boolean
         if (beforeOffset !== null && result.beforeOffset != null) {
           beforeOffsetRef.current = result.beforeOffset
           setList([...result.messages, ...mergerRef.current.list])
-          setHasMore(
-            nextLimit < MAX_MESSAGES && (result.hasMore ?? result.messages.length >= pageLimit)
-          )
+          more = nextLimit < MAX_MESSAGES && (result.hasMore ?? result.messages.length >= pageLimit)
         } else {
-          // Older runtimes ignore the cursor and return the growing tail.
-          setList(result.messages)
-          setHasMore(result.messages.length >= nextLimit)
+          // Older runtimes ignore the cursor and return the growing tail; rows that streamed in while
+          // it waited stay.
+          const live = mergerRef.current.list
+          const after = live.findIndex((message) => message.id === result.messages.at(-1)?.id)
+          const landed =
+            after === -1 ? result.messages : [...result.messages, ...live.slice(after + 1)]
+          // Only updates accepted after receipt outrank history; unchanged cached rows may be stale.
+          const changed = live.filter((message) => receivedLive.get(message.id) !== message)
+          setList(mergeNativeChatMessages(landed, changed))
+          more = result.messages.length >= nextLimit
         }
-      } catch {
-        // Nothing awaits this page, so a rejected request — a transport drop, or the client
-        // abandoning it at teardown — would otherwise reach the document as an unhandled
-        // rejection. Swallowed to match the operation's own skip policy: a page that never
-        // arrives leaves the window the subscription already delivered.
-      } finally {
-        // A late page from a prior tab must not unlock the current tab's request.
-        if (
-          sessionIdRef.current === requestSessionId &&
-          streamGenerationRef.current === requestGeneration
-        ) {
-          loadingEarlierRef.current = false
-          setLoadingEarlier(false)
-        }
-      }
-    })()
-  }, [client, agent, sessionId, transcriptPath, hasMore, setList])
+        setHasMore(more)
+        return more ? 'drew' : 'end'
+      })
+    },
+    [client, agent, sessionId, transcriptPath, hasMore, setList, loadOlderPages]
+  )
 
   // Held for any unsettled read, not just an in-flight one: a stream error or a
   // dropped client would otherwise trade the conversation for an error card.
@@ -323,7 +341,8 @@ export function useMobileNativeChatSession(args: {
     transcriptLoading: status === 'loading' || status === 'awaiting-transcript',
     error,
     hasMore,
-    loadingEarlier,
+    loadingEarlier: olderPages === 'loading',
+    olderPages,
     loadEarlier
   }
 }
diff --git a/mobile/src/session/use-mobile-native-chat-tail-follow.ts b/mobile/src/session/use-mobile-native-chat-tail-follow.ts
index 92851ab9379..05e7fa561a3 100644
--- a/mobile/src/session/use-mobile-native-chat-tail-follow.ts
+++ b/mobile/src/session/use-mobile-native-chat-tail-follow.ts
@@ -1,10 +1,7 @@
 import { useCallback, useEffect, useLayoutEffect, useRef, useState, type RefObject } from 'react'
-import {
-  Platform,
-  type FlatList,
-  type NativeScrollEvent,
-  type NativeSyntheticEvent
-} from 'react-native'
+import { Platform, type NativeScrollEvent, type NativeSyntheticEvent } from 'react-native'
+import type { MobileNativeChatScrollNode } from './MobileNativeChatScrollHold'
+import type { MobileNativeChatPageObservation } from './mobile-native-chat-page-motion'
 
 /** Distance from the bottom, in points, still treated as "at the tail". */
 const AT_TAIL_SLOP = 80
@@ -26,8 +23,23 @@ export function mobileNativeChatRowAnchor(hasHeader: boolean): { minIndexForVisi
   return hasHeader ? ANCHOR_BELOW_HEADER : ANCHOR_AT_FIRST_ROW
 }
 
-/** The part of the page list's scrollable DOM node the pin reads. */
-type PageScroller = { scrollHeight: number }
+/** The list's scrollable node on the page, as RN Web's ScrollView decorates it. */
+type PageScroller = Element & MobileNativeChatScrollNode & { getInnerViewNode: () => Element }
+
+/** RN Web reports content size a task after layout, so a frame can paint between growth and a pin
+ *  driven by that report. An observer on the scroller and its content runs before that paint. */
+function observePageResize(
+  scroller: PageScroller | null | undefined,
+  onResize: (entries: readonly ResizeObserverEntry[]) => void
+): ResizeObserver | null {
+  if (!scroller || typeof ResizeObserver === 'undefined') {
+    return null
+  }
+  const observer = new ResizeObserver(onResize)
+  observer.observe(scroller)
+  observer.observe(scroller.getInnerViewNode())
+  return observer
+}
 
 function distanceFromTail(event: NativeScrollEvent): number {
   const { contentOffset, contentSize, layoutMeasurement } = event
@@ -38,14 +50,43 @@ function isAtTail(event: NativeScrollEvent): boolean {
   return distanceFromTail(event) <= AT_TAIL_SLOP
 }
 
-export type MobileNativeChatTailFollow<TItem> = {
-  /** Attach to the transcript list; the hook scrolls through this ref alone. */
-  listRef: RefObject<FlatList<TItem> | null>
+/** What the owner and the place-hold use of a transcript list: native's FlatList, or the page's. */
+export type MobileNativeChatListHandle = {
+  getScrollableNode: () => PageScroller | null | undefined
+  scrollToOffset: (params: { animated: boolean; offset: number }) => void
+  scrollToEnd: (params: { animated: boolean }) => void
+  /** Page only: each resize, with the observer's entries; runs the end `pin` once it has counted a
+   *  move of the reader's no scroll event reported yet. */
+  afterResize?: (entries: readonly ResizeObserverEntry[], pin: () => void) => void
+  /** Page only: the list's rows join the one observer, so each reports its own height. */
+  observeWith?: (observer: ResizeObserver | null) => void
+  /** Page only: the place-hold's correction, written while the reader moves only for a regroup. */
+  keepInPlace?: (drift: number, regrouped: boolean) => void
+  /** Page only: resolves once the reader stops moving the list, or the list goes away. */
+  settled?: () => Promise<void>
+  /** Page only: each classified move, before any resize correction or end pin. */
+  watchMotion?: (fn: ((observation: MobileNativeChatPageObservation) => void) | null) => void
+  /** Page only: following changed, which decides whether the browser's anchoring may move it. */
+  syncAnchoring?: () => void
+  /** Page only: the place-hold takes the scroll from the browser's anchoring for its correction. */
+  holdPlace?: (on: boolean) => void
+}
+
+export type MobileNativeChatTailFollow = {
+  /** Spread on the native list. `ref`: the hook scrolls through it alone. */
+  listProps: { ref: (list: MobileNativeChatListHandle | null) => () => void }
+  /** Spread on the page list: the same `ref`, which also watches the list resize. */
+  pageListProps: {
+    ref: (list: MobileNativeChatListHandle | null) => () => void
+    endAnchored: boolean
+    isFollowing: () => boolean
+    pin: () => void
+  }
   /** Render flag for the jump-to-latest control. */
   showJumpToTail: boolean
   /** Passive maintenance: re-pin after the viewport resizes. */
   pinToTail: () => void
-  /** Content-size maintenance using the list's authoritative measured height. */
+  /** Content-size maintenance: native uses the measured height, the page its live end. */
   pinToTailAfterContentResize: (_width: number, height: number) => void
   /** Explicit jump — send, or the jump-to-latest control. Resumes following. */
   jumpToTail: () => void
@@ -53,9 +94,15 @@ export type MobileNativeChatTailFollow<TItem> = {
   endUserDrag: (event: NativeSyntheticEvent<NativeScrollEvent>) => void
   beginMomentum: () => void
   endMomentum: (event: NativeSyntheticEvent<NativeScrollEvent>) => void
-  /** Whether a scroll near the top is the reader's own, and so may page in older history. */
-  readerIsScrolling: () => boolean
+  /** Whether a scroll near the top may page in older history: only a native list's own drag. The
+   *  page loads it only from the "Load earlier" control, since a page landing in iOS's top bounce
+   *  gets the place-hold's write while WebKit owns the scroll, and the list stops scrolling. */
+  scrollMayLoadEarlier: () => boolean
   recordScrollMetrics: (event: NativeScrollEvent) => void
+  /** Page only: an older page waits for it, so it never lands under a reader who is scrolling. */
+  pageSettled: (() => Promise<void>) | undefined
+  /** Read at commit by the page's place-hold: the list, and whether the reader follows the end. */
+  placeHold: { listRef: RefObject<MobileNativeChatListHandle | null>; isFollowing: () => boolean }
 }
 
 /** Sole owner of transcript scroll position.
@@ -69,17 +116,17 @@ export type MobileNativeChatTailFollow<TItem> = {
  *  Intent (`following`) is kept separate from geometry (at-tail): a programmatic
  *  scroll reports metrics like any other, so letting metrics decide intent let
  *  the view argue with itself. Only the user's own gestures and explicit jumps
- *  move intent; metrics only decide where a *released* gesture leaves us.
+ *  move native intent; metrics decide where a *released* gesture leaves us. On
+ *  the page, a move toward the end resumes following; only reader input detaches it.
  */
-export function useMobileNativeChatTailFollow<TItem>(args: {
-  /** The list's rows; an empty list is never scrolled. */
-  items: readonly TItem[]
-  /** The chat shown; another one opens following, whatever the reader did in this one. */
+export function useMobileNativeChatTailFollow(args: {
+  /** Guards `scrollToEnd` against an empty list. */
+  hasItems: boolean
+  /** The chat shown; another one opens following, whatever the reader did here. */
   scopeKey: string
-}): MobileNativeChatTailFollow<TItem> {
-  const { scopeKey } = args
-  const hasItems = args.items.length > 0
-  const listRef = useRef<FlatList<TItem> | null>(null)
+}): MobileNativeChatTailFollow {
+  const { hasItems, scopeKey } = args
+  const listRef = useRef<MobileNativeChatListHandle | null>(null)
   const [following, setFollowingFlag] = useState(true)
   const [atTail, setAtTailFlag] = useState(true)
   // Event handlers read intent at event time, before a re-render lands.
@@ -87,9 +134,6 @@ export function useMobileNativeChatTailFollow<TItem>(args: {
   const atTailRef = useRef(true)
   const userScrollActiveRef = useRef(false)
   const userScrollSettleFrameRef = useRef<number | null>(null)
-  // Page only: what the offsets last said, in place of the gestures RN Web does not report.
-  const pageOffsetRef = useRef(0)
-  const pageReaderMovedUpRef = useRef(false)
   const scopeKeyRef = useRef(scopeKey)
 
   // Single writer, so the event-time ref and the render flag cannot disagree.
@@ -98,6 +142,8 @@ export function useMobileNativeChatTailFollow<TItem>(args: {
       return
     }
     followingRef.current = next
+    // Before any write or commit: the browser's anchoring and the end pin never both hold the place.
+    listRef.current?.syncAnchoring?.()
     setFollowingFlag(next)
   }, [])
 
@@ -109,30 +155,76 @@ export function useMobileNativeChatTailFollow<TItem>(args: {
     setAtTailFlag(next)
   }, [])
 
+  // Live geometry: a size report arrives late and can name an end the view has already left.
+  // Not `scrollToEnd`: its estimate can land short, and the page reads a move up as the reader's.
+  const pinPageToEnd = useCallback(() => {
+    const scroller = listRef.current?.getScrollableNode()
+    if (!followingRef.current || !scroller) {
+      return
+    }
+    const end = scroller.scrollHeight - scroller.clientHeight
+    // Already there, or iOS bouncing past an end: a write then lands while WebKit owns the scroll.
+    if (scroller.scrollTop < 0 || scroller.scrollTop >= end - PAGE_MOVE_SLOP) {
+      return
+    }
+    listRef.current?.scrollToOffset({ animated: false, offset: end })
+  }, [])
+
+  const attachList = useCallback(
+    (list: MobileNativeChatListHandle | null) => {
+      listRef.current = list
+      const page = !listReportsGestures()
+      // Following comes only from classified motion: a resize can land a parked reader on a shorter
+      // end (a collapse below them), and that clamp is layout's, not the reader asking to follow.
+      const observer = page
+        ? observePageResize(list?.getScrollableNode(), (entries) =>
+            list?.afterResize ? list.afterResize(entries, pinPageToEnd) : pinPageToEnd()
+          )
+        : null
+      list?.observeWith?.(observer)
+      // Only a move toward the end attaches: a clamp onto a shorter end moves up, even one that
+      // lands under the reader's finger (a tap on a collapse below them).
+      list?.watchMotion?.(({ by, moved, fromEnd }) => {
+        if (followingRef.current) {
+          // Any upward move of the reader's that leaves the end detaches: a slow drag reports many
+          // 1px moves, and none of them alone is past a per-event threshold.
+          if (by === 'reader' && moved < 0 && fromEnd > PAGE_MOVE_SLOP) {
+            setFollowing(false)
+          }
+        } else if (
+          (by === 'reader' && moved > 0 && fromEnd <= PAGE_MOVE_SLOP) ||
+          (by !== 'own' && moved > PAGE_MOVE_SLOP && fromEnd <= AT_TAIL_SLOP)
+        ) {
+          setFollowing(true)
+        }
+      })
+      return () => {
+        list?.watchMotion?.(null)
+        list?.observeWith?.(null)
+        observer?.disconnect()
+        listRef.current = null
+      }
+    },
+    [pinPageToEnd, setFollowing]
+  )
+
   const pinToTail = useCallback(() => {
-    if (!followingRef.current || !hasItems) {
-      return
-    }
-    if (listReportsGestures()) {
+    if (!listReportsGestures()) {
+      pinPageToEnd()
+    } else if (followingRef.current && hasItems) {
       listRef.current?.scrollToEnd({ animated: false })
-      return
     }
-    // Why not `scrollToEnd`: its estimate can land short, and the page reads a move up as the reader's.
-    // The live height: the last reported one can still be the previous chat's.
-    const scroller: PageScroller | null | undefined = listRef.current?.getScrollableNode()
-    if (scroller) {
-      listRef.current?.scrollToOffset({ animated: false, offset: scroller.scrollHeight })
-    }
-  }, [hasItems])
+  }, [hasItems, pinPageToEnd])
 
   const pinToTailAfterContentResize = useCallback(
     (_width: number, height: number) => {
-      if (!followingRef.current || !hasItems) {
-        return
+      if (!listReportsGestures()) {
+        pinPageToEnd()
+      } else if (followingRef.current && hasItems) {
+        listRef.current?.scrollToOffset({ animated: false, offset: height })
       }
-      listRef.current?.scrollToOffset({ animated: false, offset: height })
     },
-    [hasItems]
+    [hasItems, pinPageToEnd]
   )
 
   const clearUserScrollSettle = useCallback(() => {
@@ -144,24 +236,9 @@ export function useMobileNativeChatTailFollow<TItem>(args: {
 
   const recordScrollMetrics = useCallback(
     (event: NativeScrollEvent) => {
-      const endsAtTail = isAtTail(event)
-      setAtTail(endsAtTail)
-      if (listReportsGestures()) {
-        return
-      }
-      const moved = event.contentOffset.y - pageOffsetRef.current
-      pageOffsetRef.current = event.contentOffset.y
-      pageReaderMovedUpRef.current = moved < -PAGE_MOVE_SLOP
-      if (followingRef.current) {
-        // A pin only moves toward the end and a clamp lands on it: up and short of it is the reader.
-        if (pageReaderMovedUpRef.current && distanceFromTail(event) > PAGE_MOVE_SLOP) {
-          setFollowing(false)
-        }
-      } else if (moved > PAGE_MOVE_SLOP && endsAtTail) {
-        setFollowing(true)
-      }
+      setAtTail(isAtTail(event))
     },
-    [setAtTail, setFollowing]
+    [setAtTail]
   )
 
   const jumpToTail = useCallback(() => {
@@ -221,25 +298,29 @@ export function useMobileNativeChatTailFollow<TItem>(args: {
     [finishUserScroll]
   )
 
-  const readerIsScrolling = useCallback(
-    () => (listReportsGestures() ? userScrollActiveRef.current : pageReaderMovedUpRef.current),
+  const scrollMayLoadEarlier = useCallback(
+    () => listReportsGestures() && userScrollActiveRef.current,
     []
   )
 
-  // Before paint, so the next chat never shows where the reader left the last one.
+  const isFollowing = useCallback(() => followingRef.current, [])
+  const pageSettled = useCallback(() => listRef.current?.settled?.() ?? Promise.resolve(), [])
+
+  // The view stays mounted across chats: before paint, so the next one never shows where the reader
+  // left the last.
   useLayoutEffect(() => {
-    if (scopeKeyRef.current !== scopeKey) {
-      scopeKeyRef.current = scopeKey
-      pageOffsetRef.current = 0
-      pageReaderMovedUpRef.current = false
-      jumpToTail()
+    if (scopeKeyRef.current === scopeKey) {
+      return
     }
+    scopeKeyRef.current = scopeKey
+    jumpToTail()
   }, [scopeKey, jumpToTail])
 
   useEffect(() => clearUserScrollSettle, [clearUserScrollSettle])
 
   return {
-    listRef,
+    listProps: { ref: attachList },
+    pageListProps: { ref: attachList, endAnchored: following, isFollowing, pin: pinPageToEnd },
     showJumpToTail: !following && !atTail,
     pinToTail,
     pinToTailAfterContentResize,
@@ -248,7 +329,9 @@ export function useMobileNativeChatTailFollow<TItem>(args: {
     endUserDrag,
     beginMomentum,
     endMomentum,
-    readerIsScrolling,
-    recordScrollMetrics
+    scrollMayLoadEarlier,
+    recordScrollMetrics,
+    pageSettled: listReportsGestures() ? undefined : pageSettled,
+    placeHold: { listRef, isFollowing }
   }
 }
diff --git a/mobile/src/session/use-mobile-native-chat-turn-disclosure.ts b/mobile/src/session/use-mobile-native-chat-turn-disclosure.ts
index 4509969d4a8..1fd78cd7cc9 100644
--- a/mobile/src/session/use-mobile-native-chat-turn-disclosure.ts
+++ b/mobile/src/session/use-mobile-native-chat-turn-disclosure.ts
@@ -15,6 +15,7 @@ import { nativeChatMessagesWaitingBehindLiveTurn } from '../../../src/shared/nat
 import { NATIVE_CHAT_STREAMING_ID } from '../../../src/shared/native-chat-streaming'
 import type { NativeChatResolvedPrompt } from '../../../src/shared/native-chat-resolution-receipt'
 import { useMobileNativeChatTranscriptRows } from './use-mobile-native-chat-transcript-rows'
+import type { MobileNativeChatRunPresentation } from './mobile-native-chat-run-descriptors'
 import {
   nativeChatRowsInDrawOrder,
   nativeChatTurnBarRows
@@ -132,6 +133,7 @@ export function useMobileNativeChatTurnDisclosure({
   scopeKey: string
 }): {
   active: NativeChatTurnStatus | null
+  presentation: MobileNativeChatRunPresentation
   /** The live turn's provider activity copy, for the footer row. */
   activeActivityText: string | null
   onToggleTurn: (turnKey: string) => void
@@ -233,6 +235,10 @@ export function useMobileNativeChatTurnDisclosure({
     expandedTurnKeys: expandedTurnIds,
     liveReasoningId
   })
+  const presentation = useMemo(
+    () => ({ rows, workRuns, turnKeys, receipts }),
+    [rows, workRuns, turnKeys, receipts]
+  )
   const latestAssistantId = useMemo(
     () => waiting.listMessages.findLast((row) => row.role === 'assistant')?.id ?? null,
     [waiting.listMessages]
@@ -316,6 +322,7 @@ export function useMobileNativeChatTurnDisclosure({
 
   return {
     active,
+    presentation,
     activeActivityText,
     /** Stable for a given chat scope, so it never disturbs a row's memo. */
     onToggleTurn: toggleExpandedTurn,
diff --git a/mobile/src/session/use-mobile-older-page-loader.ts b/mobile/src/session/use-mobile-older-page-loader.ts
new file mode 100644
index 00000000000..b16b0f86ca8
--- /dev/null
+++ b/mobile/src/session/use-mobile-older-page-loader.ts
@@ -0,0 +1,78 @@
+import { useCallback, useRef, useState } from 'react'
+import { RPC_REQUEST_MIN_ACK_MS } from '../transport/rpc-request-budget'
+
+/** One tap's whole wait, connect included, shared by every page it reads. */
+export const OLDER_PAGE_BUDGET_MS = 15_000
+/** Bounds the pages one tap reads past pages that draw nothing. */
+export const OLDER_PAGES_PER_TAP = 8
+
+/** One page of a tap: it drew a row, drew nothing (read on), reached the end, failed in a way a
+ *  retry can get past, or met history that can never be read from there. */
+export type OlderPageStep = 'drew' | 'drew-nothing' | 'end' | 'failed' | 'unavailable'
+
+/** What the Load earlier control shows. */
+export type OlderPagePhase = 'idle' | 'loading' | 'failed' | 'unavailable'
+
+/** One request of a tap. `timeoutMs` is what is left of the tap's budget, connect included. */
+export type OlderPageReader = (request: {
+  timeoutMs: number
+  isCurrent: () => boolean
+}) => Promise<OlderPageStep>
+
+/**
+ * The one owner of an older-page read for either chat lane. A read ends by its own settlement or by
+ * `supersede()`, and both clear the spinner here, so no path can strand it.
+ */
+export function useMobileOlderPageLoader(): {
+  phase: OlderPagePhase
+  /** Starts a tap's read unless one is running. */
+  load: (reader: OlderPageReader) => void
+  /** The window the read was for is gone: ends it silently and clears the spinner and the line. */
+  supersede: () => void
+} {
+  const [phase, setPhase] = useState<OlderPagePhase>('idle')
+  // Only the running read's token may settle the phase, so a superseded read's late reply can't.
+  const tokenRef = useRef<object | null>(null)
+  // History that can't be read stays so until the window is replaced, whatever re-triggers a read.
+  const unavailableRef = useRef(false)
+
+  const load = useCallback((reader: OlderPageReader) => {
+    if (tokenRef.current || unavailableRef.current) {
+      return
+    }
+    const token = {}
+    tokenRef.current = token
+    setPhase('loading')
+    const isCurrent = (): boolean => tokenRef.current === token
+    const deadline = Date.now() + OLDER_PAGE_BUDGET_MS
+    void (async (): Promise<OlderPageStep> => {
+      let step: OlderPageStep = 'drew-nothing'
+      for (let page = 0; page < OLDER_PAGES_PER_TAP && step === 'drew-nothing'; page += 1) {
+        const timeoutMs = deadline - Date.now()
+        // Too little left to be answered: what landed stays, and the next tap reads on.
+        if (!isCurrent() || timeoutMs < RPC_REQUEST_MIN_ACK_MS) {
+          return 'end'
+        }
+        step = await reader({ timeoutMs, isCurrent })
+      }
+      return step
+    })()
+      // Contained here: nothing awaits this read, so a transport drop would be unhandled.
+      .catch((): OlderPageStep => 'failed')
+      .then((step) => {
+        if (isCurrent()) {
+          tokenRef.current = null
+          unavailableRef.current = step === 'unavailable'
+          setPhase(step === 'failed' || step === 'unavailable' ? step : 'idle')
+        }
+      })
+  }, [])
+
+  const supersede = useCallback(() => {
+    tokenRef.current = null
+    unavailableRef.current = false
+    setPhase('idle')
+  }, [])
+
+  return { phase, load, supersede }
+}
diff --git a/mobile/src/session/use-mobile-structured-agent-session-prompt-cancel.test.tsx b/mobile/src/session/use-mobile-structured-agent-session-prompt-cancel.test.tsx
index 9de2d488616..478a4d1e121 100644
--- a/mobile/src/session/use-mobile-structured-agent-session-prompt-cancel.test.tsx
+++ b/mobile/src/session/use-mobile-structured-agent-session-prompt-cancel.test.tsx
@@ -17,7 +17,7 @@ vi.mock('./use-mobile-structured-agent-state', () => ({
   useMobileStructuredAgentState: () => ({
     state,
     stateRef,
-    loadingOlder: false,
+    olderPages: 'idle',
     loadEarlier: vi.fn()
   })
 }))
diff --git a/mobile/src/session/use-mobile-structured-agent-session.ts b/mobile/src/session/use-mobile-structured-agent-session.ts
index 66fd76fda00..5916715c6b7 100644
--- a/mobile/src/session/use-mobile-structured-agent-session.ts
+++ b/mobile/src/session/use-mobile-structured-agent-session.ts
@@ -76,7 +76,7 @@ export function useMobileStructuredAgentSession(
   // Against a host that predates the quiet repeated Stop, a Stop of a turn still being stopped joins it.
   const inFlightStopsRef = useRef(new Map<string, Promise<boolean>>())
   const stateArgs = { client, sessionId, sessionKey, enabled, connected }
-  const { state, stateRef, queuedMessages, queuePause, loadingOlder, loadEarlier } =
+  const { state, stateRef, queuedMessages, queuePause, olderPages, loadEarlier } =
     useMobileStructuredAgentState(stateArgs)
 
   const mutate = useMobileStructuredAgentMutate({
@@ -291,8 +291,10 @@ export function useMobileStructuredAgentSession(
       transcriptLoading: status === 'loading',
       error: state.error,
       readFailedFinally: status === 'error' && isFinalAgentSessionReadRefusal(state.readRefusal),
-      hasMore: state.hasOlder,
-      loadingEarlier: loadingOlder,
+      // History that can never be read from here ends paging; its line says so.
+      hasMore: state.hasOlder && olderPages !== 'unavailable',
+      loadingEarlier: olderPages === 'loading',
+      olderPages,
       loadEarlier
     },
     isWorking,
diff --git a/mobile/src/session/use-mobile-structured-agent-state.test.tsx b/mobile/src/session/use-mobile-structured-agent-state.test.tsx
index fd319f12f48..d701c07465b 100644
--- a/mobile/src/session/use-mobile-structured-agent-state.test.tsx
+++ b/mobile/src/session/use-mobile-structured-agent-state.test.tsx
@@ -3,7 +3,8 @@ import { act, create, type ReactTestRenderer } from 'react-test-renderer'
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import type {
   AgentJournalCursor,
-  AgentJournalRenderItem
+  AgentJournalRenderItem,
+  AgentJournalResetReason
 } from '../../../src/shared/agent-session-journal-types'
 import type { AgentSessionHistoryPage } from '../../../src/shared/agent-session-wire'
 import type { RpcClient } from '../transport/rpc-client'
@@ -59,9 +60,10 @@ describe('useMobileStructuredAgentState older history', () => {
   })
 
   /** Mounts the hook on a session whose newest rows are `newest` (by default one of the
-   *  session's own, at 1000), with the host serving `older` by the cursor each read asks before. */
+   *  session's own, at 1000), with the host serving `older` by the cursor each read asks before:
+   *  a page, a reset, or a thrown error. */
   async function mountWithOlderPages(
-    older: Record<number, AgentSessionHistoryPage | undefined>,
+    older: Record<number, AgentSessionHistoryPage | AgentJournalResetReason | Error | undefined>,
     newest: AgentJournalRenderItem[] = [said(1_000)]
   ) {
     let onFrame: ((value: unknown) => void) | null = null
@@ -71,10 +73,16 @@ describe('useMobileStructuredAgentState older history', () => {
         return { ok: true, result: {} }
       }
       historyCursors.push(params.cursor.sequence)
-      const olderPage = older[params.cursor.sequence]
+      const olderPage = older[params.cursor.sequence] ?? 'cursor_ahead'
+      if (olderPage instanceof Error) {
+        throw olderPage
+      }
       return {
         ok: true,
-        result: olderPage ? { ok: true, page: olderPage } : { ok: false, reset: 'cursor_ahead' }
+        result:
+          typeof olderPage === 'string'
+            ? { ok: false, reset: olderPage }
+            : { ok: true, page: olderPage }
       }
     })
     const subscribe = vi.fn(
@@ -155,8 +163,34 @@ describe('useMobileStructuredAgentState older history', () => {
     const { hook, historyCursors } = await mountWithOlderPages({}, range(800, 1_000, 'task-1'))
 
     await vi.waitFor(() => expect(historyCursors).toEqual([800]))
-    await vi.waitFor(() => expect(hook.current!.loadingOlder).toBe(false))
+    await vi.waitFor(() => expect(hook.current!.olderPages).toBe('idle'))
     await new Promise((resolve) => setTimeout(resolve, 20))
     expect(historyCursors).toEqual([800])
   })
+
+  it('keeps the chat readable when an older page fails, retries on a tap, and ends at unreadable history', async () => {
+    const older: Parameters<typeof mountWithOlderPages>[0] = { 1000: new Error('timed out') }
+    const { hook } = await mountWithOlderPages(older)
+
+    act(() => hook.current!.loadEarlier())
+    await vi.waitFor(() => expect(hook.current!.olderPages).toBe('failed'))
+    expect(hook.current!.state.status).toBe('ready')
+    expect(hook.current!.state.items.map((item) => item.sequence)).toEqual([1_000])
+
+    older[1000] = page(range(900, 1_000), true)
+    older[900] = Object.assign(new Error('agent_session_journal_unreadable'), {
+      data: {
+        refusal: { code: 'agent_session_journal_unreadable', details: { reason: 'journalCorrupt' } }
+      }
+    })
+    act(() => hook.current!.loadEarlier())
+    await vi.waitFor(() => expect(hook.current!.state.items[0]?.sequence).toBe(900))
+    expect(hook.current!.olderPages).toBe('idle')
+
+    act(() => hook.current!.loadEarlier())
+    await vi.waitFor(() => expect(hook.current!.olderPages).toBe('unavailable'))
+    expect(hook.current!.state.status).toBe('ready')
+    act(() => hook.current!.loadEarlier())
+    expect(hook.current!.olderPages).toBe('unavailable')
+  })
 })
diff --git a/mobile/src/session/use-mobile-structured-agent-state.ts b/mobile/src/session/use-mobile-structured-agent-state.ts
index 208369c7ea4..0521ce41433 100644
--- a/mobile/src/session/use-mobile-structured-agent-state.ts
+++ b/mobile/src/session/use-mobile-structured-agent-state.ts
@@ -1,15 +1,14 @@
 import { openTranscriptAfterHold } from './mobile-structured-transcript-subscription'
 import { startMobileStructuredTranscriptRead } from './mobile-structured-transcript-read'
 import { useCallback, useEffect, useLayoutEffect, useRef, useState } from 'react'
-import type { AgentJournalCursor } from '../../../src/shared/agent-session-journal-types'
 import { isRootAgentJournalItem } from '../../../src/shared/agent-session-journal-producer'
 import type {
-  AgentSessionHistoryPage,
   AgentSessionHistoryResult,
   AgentSessionSubscribeEvent
 } from '../../../src/shared/agent-session-wire'
 import { AGENT_SESSION_HISTORY_MAX_LIMIT } from '../../../src/shared/agent-session-wire'
 import { structuredAgentSessionHolderId } from '../../../src/shared/structured-agent-session-holder'
+import { isFinalAgentSessionReadRefusal } from '../../../src/shared/structured-agent-session-read-refusal'
 import {
   EMPTY_STRUCTURED_AGENT_SESSION,
   oldestStructuredAgentSessionCursor,
@@ -29,6 +28,7 @@ import {
   type MobileQueuedMessageFeed,
   type MobileQueuePause
 } from './mobile-structured-queued-message-feed'
+import { useMobileOlderPageLoader, type OlderPagePhase } from './use-mobile-older-page-loader'
 
 type QueuedFeed = {
   messages: MobileQueuedMessageFeed
@@ -37,10 +37,6 @@ type QueuedFeed = {
 const NO_QUEUED_FEED: QueuedFeed = { messages: null, pause: null }
 
 const MAX_RETAINED_SESSION_STATES = 32
-/** Bounded so a busy stream cannot turn one Load-earlier tap into an endless read chain. */
-const OLDER_PAGE_ANCHOR_ATTEMPTS = 3
-/** Bounds the pages one Load-earlier reads past that hold only subagent rows. */
-const OLDER_PAGES_PER_LOAD = 8
 
 export function useMobileStructuredAgentState(args: {
   client: RpcClient | null
@@ -57,8 +53,9 @@ export function useMobileStructuredAgentState(args: {
   queuedMessages: MobileQueuedMessageFeed
   /** The whole queue's pause, published with the drafts. */
   queuePause: MobileQueuePause
-  loadingOlder: boolean
-  loadEarlier: () => void
+  olderPages: OlderPagePhase
+  /** `settled`: the page waits for it before it lands (the phone page, until the reader stops). */
+  loadEarlier: (settled?: () => Promise<void>) => void
 } {
   const { client, connected, enabled, sessionId, sessionKey } = args
   // Keep a bounded cache so offline tab switches select the right transcript
@@ -74,14 +71,11 @@ export function useMobileStructuredAgentState(args: {
   const queued =
     (enabled && sessionKey ? queuedBySession.get(sessionKey) : undefined) ?? NO_QUEUED_FEED
   const queuedMessages = queued.messages
-  const [loadingOlder, setLoadingOlder] = useState(false)
+  const { phase: olderPages, load: loadOlderPages, supersede } = useMobileOlderPageLoader()
   const stateRef = useRef(state)
-  const sessionKeyRef = useRef(sessionKey)
-  const streamGenerationRef = useRef(0)
   useLayoutEffect(() => {
     stateRef.current = state
-    sessionKeyRef.current = sessionKey
-  }, [sessionKey, state])
+  }, [state])
 
   const apply = useCallback(
     (action: StructuredAgentSessionAction) => {
@@ -151,9 +145,7 @@ export function useMobileStructuredAgentState(args: {
   )
 
   useEffect(() => {
-    streamGenerationRef.current += 1
-    sessionKeyRef.current = sessionKey
-    setLoadingOlder(false)
+    supersede()
     if (!client || !sessionId || !enabled) {
       return
     }
@@ -163,7 +155,7 @@ export function useMobileStructuredAgentState(args: {
       return
     }
     apply({ type: 'loading' })
-    const generation = streamGenerationRef.current
+    let streamCurrent = true
     const holderId = structuredAgentSessionHolderId('mobile-chat')
     const held = callAgentSession(client, 'agentSession.hold', {
       sessionId,
@@ -173,12 +165,23 @@ export function useMobileStructuredAgentState(args: {
       sessionId,
       open: (onFrame) => openTranscriptAfterHold(client, sessionId, held, onFrame),
       read: (request) => callAgentSession(client, 'agentSession.currentRequests', request),
-      apply,
+      apply: (action) => {
+        if (
+          action.type === 'event' &&
+          (action.event.type === 'snapshot' || action.event.type === 'reset')
+        ) {
+          // A replaced window ends an older read that was for the old one.
+          supersede()
+        }
+        apply(action)
+      },
       applyQueued,
       error: applyReadFailure,
-      isCurrent: () => generation === streamGenerationRef.current
+      isCurrent: () => streamCurrent
     })
     return () => {
+      streamCurrent = false
+      supersede()
       endStream()
       void held
         .then(() =>
@@ -195,86 +198,84 @@ export function useMobileStructuredAgentState(args: {
         )
         .catch(() => undefined)
     }
-  }, [apply, applyQueued, applyReadFailure, client, connected, enabled, sessionId, sessionKey])
+  }, [
+    apply,
+    applyQueued,
+    applyReadFailure,
+    client,
+    connected,
+    enabled,
+    sessionId,
+    sessionKey,
+    supersede
+  ])
 
-  const loadEarlier = useCallback(() => {
-    const current = stateRef.current
-    if (!client || !sessionId || !sessionKey || loadingOlder || !current.hasOlder) {
-      return
-    }
-    if (!oldestStructuredAgentSessionCursor(current)) {
-      return
-    }
-    const requestSessionKey = sessionKey
-    const requestGeneration = streamGenerationRef.current
-    const isCurrentRead = (): boolean =>
-      sessionKeyRef.current === requestSessionKey &&
-      streamGenerationRef.current === requestGeneration
-    setLoadingOlder(true)
-    void (async () => {
-      // A live batch can head-trim past the anchor mid-read, and the reducer drops that
-      // page rather than leave a hole in the transcript. Re-anchor and retry.
-      for (let attempt = 0; attempt < OLDER_PAGE_ANCHOR_ATTEMPTS; attempt += 1) {
-        const cursor = oldestStructuredAgentSessionCursor(stateRef.current)
-        if (!cursor || !isCurrentRead()) {
-          return
+  const loadEarlier = useCallback(
+    (settled?: () => Promise<void>) => {
+      const start = oldestStructuredAgentSessionCursor(stateRef.current)
+      if (!client || !sessionId || !sessionKey || !stateRef.current.hasOlder || !start) {
+        return
+      }
+      let cursor = start
+      // Every head this tap produced. Any other head means a live batch trimmed the window mid-tap,
+      // and the reducer drops a page that no longer abuts it, so the read restarts from that head.
+      // Holding them all keeps the check right while `stateRef` lags a commit behind a landed page.
+      let heads = new Set([start.sequence])
+      const intact = (): boolean => {
+        const head = oldestStructuredAgentSessionCursor(stateRef.current)
+        return head?.epoch === cursor.epoch && heads.has(head.sequence)
+      }
+      loadOlderPages(async ({ timeoutMs, isCurrent }) => {
+        if (!intact()) {
+          const head = oldestStructuredAgentSessionCursor(stateRef.current)
+          if (!head) {
+            return 'end'
+          }
+          cursor = head
+          heads = new Set([head.sequence])
         }
-        // Mobile draws only the session's own rows, so a page of a subagent's rows alone
-        // would land as nothing; read on until a page adds a row the reader can see. Older
-        // hosts send one for any burst; current ones when the page's byte bound cuts it short.
-        const pages: {
-          requestedCursor: AgentJournalCursor
-          page: AgentSessionHistoryPage
-        }[] = []
-        let requestedCursor = cursor
-        while (pages.length < OLDER_PAGES_PER_LOAD) {
-          const result = await callAgentSession<AgentSessionHistoryResult>(
+        let result: AgentSessionHistoryResult
+        try {
+          result = await callAgentSession<AgentSessionHistoryResult>(
             client,
             'agentSession.history',
-            {
-              sessionId,
-              direction: 'before',
-              cursor: requestedCursor,
-              limit: AGENT_SESSION_HISTORY_MAX_LIMIT
-            }
+            { sessionId, direction: 'before', cursor, limit: AGENT_SESSION_HISTORY_MAX_LIMIT },
+            timeoutMs
           )
-          if (!result.ok || !isCurrentRead()) {
-            break
-          }
-          pages.push({ requestedCursor, page: result.page })
-          if (
-            !result.page.hasOlder ||
-            result.page.items.length === 0 ||
-            result.page.items.some(isRootAgentJournalItem)
-          ) {
-            break
-          }
-          requestedCursor = result.page.window.nextCursor
+        } catch (error) {
+          return isFinalAgentSessionReadRefusal(agentSessionReadFailureRefusal(error))
+            ? 'unavailable'
+            : 'failed'
         }
-        if (pages.length === 0 || !isCurrentRead()) {
-          return
+        // Lands once the reader stops scrolling, so nothing grows above them mid-fling.
+        if (settled) {
+          await settled()
         }
-        // The reducer drops a page whose anchor slid, so only an intact anchor lands;
-        // each later page abuts the one before it.
-        if (oldestStructuredAgentSessionCursor(stateRef.current)?.sequence === cursor.sequence) {
-          for (const { requestedCursor: pageCursor, page } of pages) {
-            apply({ type: 'older-page', requestedCursor: pageCursor, page })
-          }
-          return
+        if (!isCurrent()) {
+          return 'end'
         }
-      }
-    })()
-      .catch((error: unknown) => {
-        if (isCurrentRead()) {
-          applyReadFailure(error)
+        if (!result.ok) {
+          // Every reset reason makes the subscription reload a fresh window, which replaces this one.
+          return 'end'
         }
+        if (!intact()) {
+          return 'drew-nothing'
+        }
+        const { page } = result
+        apply({ type: 'older-page', requestedCursor: cursor, page })
+        const oldest = page.items[0]
+        if (!page.hasOlder || !oldest) {
+          return 'end'
+        }
+        heads.add(oldest.sequence)
+        cursor = page.window.nextCursor
+        // Mobile draws only the session's own rows, so a page of a subagent's rows alone lands as
+        // nothing; the loader reads on until a page adds a row the reader can see.
+        return page.items.some(isRootAgentJournalItem) ? 'drew' : 'drew-nothing'
       })
-      .finally(() => {
-        if (isCurrentRead()) {
-          setLoadingOlder(false)
-        }
-      })
-  }, [apply, applyReadFailure, client, loadingOlder, sessionId, sessionKey])
+    },
+    [apply, client, loadOlderPages, sessionId, sessionKey]
+  )
 
   // A window of only a subagent's rows draws nothing, and an empty list cannot be scrolled
   // to ask for more, so it reads back once from each such head. A first page can be one: an
@@ -284,13 +285,18 @@ export function useMobileStructuredAgentState(args: {
       ? `${sessionKey}:${state.epoch}:${state.items[0]?.sequence}`
       : null
   const readBackFromRef = useRef<string | null>(null)
+  const loadingEarlier = olderPages === 'loading'
   useEffect(() => {
-    if (drawsNothingFrom === null || loadingOlder || readBackFromRef.current === drawsNothingFrom) {
+    if (
+      drawsNothingFrom === null ||
+      loadingEarlier ||
+      readBackFromRef.current === drawsNothingFrom
+    ) {
       return
     }
     readBackFromRef.current = drawsNothingFrom
     loadEarlier()
-  }, [drawsNothingFrom, loadEarlier, loadingOlder])
+  }, [drawsNothingFrom, loadEarlier, loadingEarlier])
 
-  return { state, stateRef, queuedMessages, queuePause: queued.pause, loadingOlder, loadEarlier }
+  return { state, stateRef, queuedMessages, queuePause: queued.pause, olderPages, loadEarlier }
 }
diff --git a/mobile/src/terminal/terminal-web-document-mount.test.ts b/mobile/src/terminal/terminal-web-document-mount.test.ts
index 98bef5fbbd7..08833bc9092 100644
--- a/mobile/src/terminal/terminal-web-document-mount.test.ts
+++ b/mobile/src/terminal/terminal-web-document-mount.test.ts
@@ -170,8 +170,12 @@ describe('the page keeps its own capture buffer', () => {
     const posted: Array<Record<string, unknown>> = []
     const mounted = mountTerminalWebDocument(host, (message) => posted.push(message))
 
-    window.dispatchEvent(new ErrorEvent('error', { message: 'first failure' }))
-    window.dispatchEvent(new ErrorEvent('error', { message: 'second failure' }))
+    window.dispatchEvent(
+      new ErrorEvent('error', { message: 'first failure', error: new Error('first failure') })
+    )
+    window.dispatchEvent(
+      new ErrorEvent('error', { message: 'second failure', error: new Error('second failure') })
+    )
 
     const messages = posted.filter((message) => message.type === 'error').map((m) => m.message)
     expect(messages[0]).toContain('captured: first failure')
@@ -182,12 +186,27 @@ describe('the page keeps its own capture buffer', () => {
     const nextHost = plantHost()
     const nextPosted: Array<Record<string, unknown>> = []
     const next = mountTerminalWebDocument(nextHost, (message) => nextPosted.push(message))
-    window.dispatchEvent(new ErrorEvent('error', { message: 'third failure' }))
+    window.dispatchEvent(
+      new ErrorEvent('error', { message: 'third failure', error: new Error('third failure') })
+    )
     const nextMessages = nextPosted.filter((m) => m.type === 'error').map((m) => m.message)
     expect(nextMessages[0]).toContain('captured: third failure')
     expect(nextMessages[0]).not.toContain('first failure')
     next.dispose()
   })
+
+  it("leaves a browser notice from elsewhere on the page out, so it can't fail a terminal", () => {
+    // The chat list's resize observer can make the browser raise its loop notice; no error is behind it.
+    const host = plantHost()
+    const posted: Array<Record<string, unknown>> = []
+    const mounted = mountTerminalWebDocument(host, (message) => posted.push(message))
+
+    const message = 'ResizeObserver loop completed with undelivered notifications.'
+    window.dispatchEvent(new ErrorEvent('error', { message }))
+
+    expect(posted.filter((m) => m.type === 'error')).toEqual([])
+    mounted.dispose()
+  })
 })
 
 describe('a start that throws gives the host back', () => {
diff --git a/mobile/src/terminal/terminal-web-document-mount.ts b/mobile/src/terminal/terminal-web-document-mount.ts
index b16afa80095..9ab0dc5b8a4 100644
--- a/mobile/src/terminal/terminal-web-document-mount.ts
+++ b/mobile/src/terminal/terminal-web-document-mount.ts
@@ -217,6 +217,11 @@ function startPageDocument(
     // `stopHostNotify` takes it off with everything else.
     installErrorReporter: (report) => {
       const errorListener = (event: ErrorEvent) => {
+        // The window is the whole app's: a browser notice with no error behind it (a ResizeObserver
+        // loop elsewhere on the page) is not this terminal failing, and before ready it is fatal.
+        if (!event.error) {
+          return
+        }
         report(event.message, event.filename, event.lineno, event.colno, event.error)
       }
       window.addEventListener('error', errorListener)