From b7a1aeda5d286e48d52b7f141e5eabaeeac05a77 Mon Sep 17 00:00:00 2001
From: OrcaWin <alpha-eng@stably.ai>
Date: Sat, 12 Sep 2026 18:09:22 -0700
Subject: [PATCH] perf: avoid per-item arrays in journal projection (#20305)

Co-authored-by: Orca Worker <orca-worker@localhost>
---
 src/shared/structured-agent-session-projection.ts | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/shared/structured-agent-session-projection.ts b/src/shared/structured-agent-session-projection.ts
index e0189ed7124..68e8caf22eb 100644
--- a/src/shared/structured-agent-session-projection.ts
+++ b/src/shared/structured-agent-session-projection.ts
@@ -137,10 +137,14 @@ const projectedItems = new WeakMap<AgentJournalRenderItem, NativeChatMessage | n
 export function projectStructuredItemsToNativeChat(
   items: readonly AgentJournalRenderItem[]
 ): NativeChatMessage[] {
-  return items.flatMap((item) => {
+  const messages: NativeChatMessage[] = []
+  items.forEach((item) => {
     const projected = projectStructuredItemToNativeChat(item)
-    return projected ? [projected] : []
+    if (projected) {
+      messages.push(projected)
+    }
   })
+  return messages
 }
 
 export function projectStructuredItemToNativeChat(