From f5024d4e534d63cd0db99c109f68a9acf4b72e1f Mon Sep 17 00:00:00 2001
From: Leo Li <cheerleaderleo@outlook.com>
Date: Wed, 30 Sep 2026 02:11:11 -0700
Subject: [PATCH 1/2] test(agent-chat): cover per-turn plan scope and plan
 activity keys

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 agent-chat/test/plan-scope.test.ts | 38 ++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 agent-chat/test/plan-scope.test.ts

diff --git a/agent-chat/test/plan-scope.test.ts b/agent-chat/test/plan-scope.test.ts
new file mode 100644
index 000000000000..8df1fc71279d
--- /dev/null
+++ b/agent-chat/test/plan-scope.test.ts
@@ -0,0 +1,38 @@
+import { expect, test } from "bun:test";
+
+Object.defineProperty(globalThis, "location", {
+  configurable: true,
+  value: { pathname: "/" },
+});
+
+const { activityTailKey } = await import("../src/activity");
+const { foldEvent } = await import("../src/session");
+const { groupTurns } = await import("../src/turns");
+
+const firstPlan = {
+  kind: "plan" as const,
+  entries: [{ text: "First turn", status: "in_progress" as const }],
+};
+
+test("keeps plans in the turn where they arrive", () => {
+  const blocks = foldEvent(
+    foldEvent(foldEvent([], firstPlan), { kind: "user", text: "next turn" }),
+    { kind: "plan", entries: [{ text: "Second turn", status: "pending" }] },
+  );
+  const groups = groupTurns(blocks);
+
+  expect(groups).toHaveLength(2);
+  expect(groups.map((group) => group.activity.filter((block) => block.kind === "plan").length)).toEqual([1, 1]);
+  expect(groups[0]?.activity).toContainEqual(firstPlan);
+  expect(groups[1]?.activity).toContainEqual({
+    kind: "plan",
+    entries: [{ text: "Second turn", status: "pending" }],
+  });
+});
+
+test("refreshes the activity key when a plan entry changes status", () => {
+  const pending = [{ kind: "plan" as const, entries: [{ text: "long text that is not part of the key", status: "pending" as const }] }];
+  const inProgress = [{ kind: "plan" as const, entries: [{ text: "a different long text", status: "in_progress" as const }] }];
+
+  expect(activityTailKey(pending)).not.toBe(activityTailKey(inProgress));
+});

From 1daa7434362fb3d2a6f45acb8809d761a6b1f228 Mon Sep 17 00:00:00 2001
From: Leo Li <cheerleaderleo@outlook.com>
Date: Wed, 30 Sep 2026 02:13:01 -0700
Subject: [PATCH 2/2] fix(agent-chat): keep a plan in its own turn and refresh
 the activity key

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 agent-chat/adapters/acp.ts | 4 ++--
 agent-chat/src/activity.ts | 4 ++++
 agent-chat/src/session.ts  | 9 ++++++++-
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/agent-chat/adapters/acp.ts b/agent-chat/adapters/acp.ts
index 59cd139d6034..e2c5dd4c6d77 100644
--- a/agent-chat/adapters/acp.ts
+++ b/agent-chat/adapters/acp.ts
@@ -458,7 +458,7 @@ function normalizeAcpPlanStatus(status: unknown): AgentPlanStatus {
   return status === "pending" || status === "in_progress" || status === "completed" ? status : "unknown";
 }
 
-export function normalizeAcpPlanEntries(entries: unknown): AgentPlanEntry[] {
+function normalizeAcpPlanEntries(entries: unknown): AgentPlanEntry[] {
   if (!Array.isArray(entries)) return [];
   return entries.map((entry: any) => ({
     text: typeof entry?.content === "string" ? entry.content : String(entry?.content ?? ""),
@@ -467,7 +467,7 @@ export function normalizeAcpPlanEntries(entries: unknown): AgentPlanEntry[] {
   }));
 }
 
-export function acpPlanEvent(entries: unknown): Extract<AgentEvent, { kind: "plan" }> | null {
+function acpPlanEvent(entries: unknown): Extract<AgentEvent, { kind: "plan" }> | null {
   const normalized = normalizeAcpPlanEntries(entries);
   return normalized.length ? { kind: "plan", entries: normalized } : null;
 }
diff --git a/agent-chat/src/activity.ts b/agent-chat/src/activity.ts
index e325ffcc95bc..4d963bde5f97 100644
--- a/agent-chat/src/activity.ts
+++ b/agent-chat/src/activity.ts
@@ -20,6 +20,10 @@ export function activityTailKey(blocks: Block[]): string {
   const prefix = `${blocks.length}:`;
   if (tail.kind === "assistant" || tail.kind === "thinking") return `${prefix}${tail.kind}:${tail.open}`;
   if (tail.kind === "tool") return `${prefix}${tail.kind}:${tail.toolId}:${tail.status}`;
+  if (tail.kind === "plan") {
+    const state = tail.entries.map((entry) => [entry.status, entry.priority ?? null]);
+    return `${prefix}${tail.kind}:${JSON.stringify(state)}`;
+  }
   if (tail.kind === "footer" || tail.kind === "status" || tail.kind === "error" || tail.kind === "user") {
     return `${prefix}${tail.kind}`;
   }
diff --git a/agent-chat/src/session.ts b/agent-chat/src/session.ts
index 9a8c008ada2f..48426053b769 100644
--- a/agent-chat/src/session.ts
+++ b/agent-chat/src/session.ts
@@ -214,7 +214,14 @@ export function foldEvent(blocks: Block[], evt: AgentEvent): Block[] {
       return [...closeStreaming(blocks), { kind: "status", text: evt.text }];
     case "plan": {
       const closed = closeStreaming(blocks);
-      const existingIndex = closed.findIndex((block) => block.kind === "plan");
+      let currentTurnStart = 0;
+      for (let index = closed.length - 1; index >= 0; index -= 1) {
+        if (closed[index]?.kind === "user") {
+          currentTurnStart = index + 1;
+          break;
+        }
+      }
+      const existingIndex = closed.findIndex((block, index) => index >= currentTurnStart && block.kind === "plan");
       const plan = { kind: "plan" as const, entries: evt.entries };
       if (existingIndex < 0) return [...closed, plan];
       return closed.reduce<Block[]>((next, block, index) => {