diff --git a/backend/crates/providers/openai/src/transport/correlation.rs b/backend/crates/providers/openai/src/transport/correlation.rs
index 0a639e5f8..44b216317 100644
--- a/backend/crates/providers/openai/src/transport/correlation.rs
+++ b/backend/crates/providers/openai/src/transport/correlation.rs
@@ -7,21 +7,18 @@ use sha2::{Digest, Sha256};
 use super::automatic_context::{locate_contexts, rewrite_git_context};
 use super::request::serialize_ascii_turn_metadata;
 
+// 轮次及父子轮次引用保留客户端原值，避免改变官方轮次身份与 UUIDv7 语义
 const ID_FIELDS: &[&str] = &[
     "session_id",
     "thread_id",
-    "turn_id",
     "window_id",
     "context_window_id",
     "parent_thread_id",
-    "parent_turn_id",
-    "root_turn_id",
     "forked_from_thread_id",
     "conversation_id",
     "x-codex-window-id",
     "x-codex-parent-thread-id",
     "x-client-request-id",
-    "x-client-turn-id",
     "codexWindowId",
     "parentThreadId",
 ];
@@ -39,8 +36,6 @@ const ID_HEADERS: &[&str] = &[
     "x-codex-window-id",
     "x-codex-parent-thread-id",
     "x-client-request-id",
-    "x-client-turn-id",
-    "x-codex-image-turn-id",
 ];
 
 fn scoped_id(installation_id: &str, original: &str) -> String {
@@ -206,16 +201,6 @@ pub(super) fn scope_request(
     let Some(installation_id) = installation_id else {
         return;
     };
-    // 输入项的轮次引用与请求 metadata 共用账号域，保留 item/call ID 和业务元数据
-    if let Some(Value::Array(input)) = body.get_mut("input") {
-        for item in input {
-            if let Some(Value::Object(metadata)) =
-                item.get_mut("internal_chat_message_metadata_passthrough")
-            {
-                map_fields(metadata, installation_id, &["turn_id"]);
-            }
-        }
-    }
     // 只处理官方自动 Git 上下文的关联字段，不扫描普通用户输入和工具输出
     let Ok(targets) = locate_contexts(body, true, || Ok(())) else {
         return;
@@ -229,11 +214,7 @@ pub(super) fn scope_request(
         }
         let _ = rewrite_git_context(text, 1024 * 1024, |value| {
             Ok(value.as_object_mut().map_or(0, |object| {
-                map_fields(
-                    object,
-                    installation_id,
-                    &["sessionId", "threadId", "clientUserMessageId"],
-                )
+                map_fields(object, installation_id, &["sessionId", "threadId"])
             }))
         });
     }
diff --git a/backend/crates/providers/openai/tests/provider/contract/correlation.rs b/backend/crates/providers/openai/tests/provider/contract/correlation.rs
index 652654304..58889c1e5 100644
--- a/backend/crates/providers/openai/tests/provider/contract/correlation.rs
+++ b/backend/crates/providers/openai/tests/provider/contract/correlation.rs
@@ -1,4 +1,4 @@
-//! 账号追踪域的稳定性、HTTP/WS 一致性、父子引用与工具端点归属回归
+//! 账号追踪域的稳定性、轮次原值透传、HTTP/WS 一致性与工具端点归属回归
 
 use super::*;
 
@@ -39,6 +39,7 @@ fn payload(websocket: bool) -> ProtocolPayload {
         "model":"gpt-5.4", "input":input,
         "prompt_cache_key":"custom-cache-key", "client_metadata":{
             "session_id":"source-session", "thread_id":"source-thread", "turn_id":"source-turn",
+            "x-client-turn-id":"source-turn",
             "x-codex-window-id":"source-window", "x-codex-parent-thread-id":"source-session",
             "x-codex-turn-metadata":full.to_string(),
             "ws_request_header_traceparent":"00-11111111111111111111111111111111-2222222222222222-01",
@@ -50,6 +51,7 @@ fn payload(websocket: bool) -> ProtocolPayload {
         ("thread_id".into(), json!("source-thread")),
         ("turn_metadata".into(), json!(metadata().to_string())),
         ("opaque_request_headers".into(), json!([
+            ["x-client-turn-id",STANDARD.encode("source-turn")],
             ["traceparent",STANDARD.encode("00-11111111111111111111111111111111-2222222222222222-01")],
             ["tracestate",STANDARD.encode("vendor=source")]
         ])),
@@ -57,7 +59,7 @@ fn payload(websocket: bool) -> ProtocolPayload {
 }
 
 #[tokio::test]
-async fn account_correlation_is_stable_across_transports_and_changes_only_with_account() {
+async fn account_correlation_preserves_turns_across_transports_and_account_switches() {
     let stores = [
         Arc::new(MemoryAccountStore::default()),
         Arc::new(MemoryAccountStore::default()),
@@ -140,7 +142,6 @@ async fn account_correlation_is_stable_across_transports_and_changes_only_with_a
             for (field, original) in [
                 ("session_id", "source-session"),
                 ("thread_id", "source-thread"),
-                ("turn_id", "source-turn"),
             ] {
                 assert_scoped_id(flat[field].as_str().unwrap(), original);
                 assert_eq!(flat[field], header[field]);
@@ -148,10 +149,16 @@ async fn account_correlation_is_stable_across_transports_and_changes_only_with_a
             }
             assert_eq!(headers["session-id"].to_str().unwrap(), flat["session_id"]);
             assert_eq!(headers["thread-id"].to_str().unwrap(), flat["thread_id"]);
+            assert_eq!(headers["x-client-turn-id"], "source-turn");
+            assert_eq!(flat["x-client-turn-id"], "source-turn");
+            assert_eq!(flat["turn_id"], "source-turn");
+            for metadata in [&header, &full] {
+                assert_eq!(metadata["turn_id"], "source-turn");
+                assert_eq!(metadata["parent_turn_id"], "source-turn");
+                assert_eq!(metadata["root_turn_id"], "source-turn");
+            }
             assert_eq!(full["parent_thread_id"], flat["session_id"]);
             assert_eq!(full["forked_from_thread_id"], flat["session_id"]);
-            assert_eq!(full["parent_turn_id"], flat["turn_id"]);
-            assert_eq!(full["root_turn_id"], flat["turn_id"]);
             assert_eq!(full["window_id"], full["context_window_id"]);
             assert!(header.get("tool_namespaces_info").is_none());
             assert_eq!(full["tool_namespaces_info"]["inventory"], "body-only");
@@ -162,7 +169,7 @@ async fn account_correlation_is_stable_across_transports_and_changes_only_with_a
                 json!({"turn_id":flat["turn_id"], "content_item_kinds":["additional_content.codex_git_state"]}),
             );
             let previous_turn = &input[1]["internal_chat_message_metadata_passthrough"]["turn_id"];
-            assert_scoped_id(previous_turn.as_str().unwrap(), "source-previous-turn");
+            assert_eq!(previous_turn, "source-previous-turn");
             assert_ne!(previous_turn, &flat["turn_id"]);
             let mut expected_history = account_isolation::isolation_history();
             for (index, item) in expected_history
@@ -176,11 +183,11 @@ async fn account_correlation_is_stable_across_transports_and_changes_only_with_a
                     .unwrap()
                     .entry("internal_chat_message_metadata_passthrough")
                     .or_insert_with(|| json!({}));
-                metadata["turn_id"] = if index == 3 {
-                    flat["turn_id"].clone()
+                metadata["turn_id"] = json!(if index == 3 {
+                    "source-turn"
                 } else {
-                    previous_turn.clone()
-                };
+                    "source-previous-turn"
+                });
             }
             assert_eq!(json!(&input[1..]), expected_history);
             let document =
@@ -224,11 +231,11 @@ async fn account_correlation_is_stable_across_transports_and_changes_only_with_a
     assert_eq!(captures[4], captures[5]);
     assert_ne!(captures[0].0, captures[4].0);
     assert_ne!(captures[0].1, captures[4].1);
-    assert_ne!(captures[0].2, captures[4].2);
+    assert_eq!(captures[0].2, captures[4].2);
 }
 
 #[tokio::test]
-async fn image_generation_and_edit_share_the_selected_account_turn_identity() {
+async fn image_generation_and_edit_preserve_the_client_turn_identity() {
     let store = Arc::new(MemoryAccountStore::default());
     create_account(&store, "acct_provider_contract").await;
     let server = MockServer::start().await;
@@ -263,7 +270,7 @@ async fn image_generation_and_edit_share_the_selected_account_turn_identity() {
     }
     let requests = server.received_requests().await.unwrap();
     let first = &requests[0].headers["x-codex-image-turn-id"];
-    assert_scoped_id(first.to_str().unwrap(), "source-turn");
+    assert_eq!(first, "source-turn");
     for request in &requests {
         assert_eq!(request.body.as_slice(), body.as_ref());
         assert_eq!(&request.headers["x-codex-image-turn-id"], first);
diff --git a/backend/crates/providers/openai/tests/provider/contract/mod.rs b/backend/crates/providers/openai/tests/provider/contract/mod.rs
index 8bfcc6c0c..d6b86a591 100644
--- a/backend/crates/providers/openai/tests/provider/contract/mod.rs
+++ b/backend/crates/providers/openai/tests/provider/contract/mod.rs
@@ -2789,13 +2789,7 @@ async fn image_endpoints_bypass_only_the_text_catalog_and_preserve_the_current_c
         Mock::given(method("POST"))
             .and(path(*endpoint))
             .and(header("originator", "codex_cli_rs"))
-            .and(|request: &wiremock::Request| {
-                request
-                    .headers
-                    .get("x-codex-image-turn-id")
-                    .and_then(|value| value.to_str().ok())
-                    .is_some_and(|value| uuid::Uuid::parse_str(value).is_ok())
-            })
+            .and(header("x-codex-image-turn-id", "turn_image_contract"))
             .and(header("version", "0.144.0"))
             .and(header("accept", "*/*"))
             .and(body_bytes(body.to_vec()))
@@ -3636,7 +3630,7 @@ async fn standalone_search_preserves_wire_and_scopes_turn_metadata_to_the_select
     let metadata: Value = serde_json::from_slice(&metadata_values[0]).expect("turn metadata JSON");
     assert_scoped_id(metadata["session_id"].as_str().unwrap(), "session");
     assert_scoped_id(metadata["thread_id"].as_str().unwrap(), "thread");
-    assert_scoped_id(metadata["turn_id"].as_str().unwrap(), "turn");
+    assert_eq!(metadata["turn_id"], "turn");
     assert_eq!(metadata.get("future"), Some(&json!(true)));
     assert!(metadata.get("account_id").is_none());
     assert_ne!(
diff --git a/docs/api.md b/docs/api.md
index 724723548..325e19aa1 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -298,13 +298,13 @@ Responses 也不透传 `x-stainless-*`、`Origin`、`Referer`、`sec-ch-ua*` 和
 出站移除下游的 `traceparent`、`tracestate` 及 WS metadata 中对应的
 `ws_request_header_traceparent`、`ws_request_header_tracestate`
 
-会话、线程、轮次、窗口及父子引用在出站时按账号安装身份稳定映射为 UUID；
+会话、线程、窗口及父子线程引用在出站时按账号安装身份稳定映射为 UUID；
 同账号保留引用关系，换账号使用不同标识。HTTP 请求头、正文 metadata、WS 副本及
 已识别的 Desktop 自动 Git 上下文使用一致映射。
-输入项的 `internal_chat_message_metadata_passthrough.turn_id` 同步映射，
-保留历史轮次与当前轮次的引用关系，其余输入项元数据保持不变。
-Images 的 `x-codex-image-turn-id`、turn metadata 和 Search 的会话 `id` 使用同一账号域；
-Search 只替换该 `id` 的原始字节，其余正文保持不变。
+轮次及父子轮次引用保留客户端原值，包括输入项的 `internal_chat_message_metadata_passthrough.turn_id`、
+请求 metadata 中的 `turn_id`、`parent_turn_id`、`root_turn_id`，以及 `x-client-turn-id`、
+Images 的 `x-codex-image-turn-id` 和 Desktop 自动 Git 上下文的 `clientUserMessageId`。
+输入项元数据保持不变。Search 的会话 `id` 按同一账号域映射，只替换该值的原始字节，其余正文保持不变。
 `prompt_cache_key` 同样按账号映射，保留同账号内的缓存共享关系；未提供时不补造。
 续接 response ID、历史 item/call ID、业务正文和未知扩展不参与映射，
 该处理减少显式追踪标识的跨账号复用，不保证会话内容或业务 metadata 无法关联