From 48178d44db155920826fdda976dcfc93780b57d5 Mon Sep 17 00:00:00 2001
From: tt-a1i <53142663+tt-a1i@users.noreply.github.com>
Date: Sat, 20 Jun 2026 12:51:21 +0800
Subject: [PATCH] fix(acp): fallback unknown turn end reasons

---
 .changeset/acp-stop-reason-fallback.md       |  5 +++++
 packages/acp-adapter/src/events-map.ts       |  4 ++++
 packages/acp-adapter/test/events-map.test.ts | 17 +++++++++++++++++
 3 files changed, 26 insertions(+)
 create mode 100644 .changeset/acp-stop-reason-fallback.md
 create mode 100644 packages/acp-adapter/test/events-map.test.ts

diff --git a/.changeset/acp-stop-reason-fallback.md b/.changeset/acp-stop-reason-fallback.md
new file mode 100644
index 000000000..11407bdd0
--- /dev/null
+++ b/.changeset/acp-stop-reason-fallback.md
@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Fallback ACP turn-end stop reason mapping to `end_turn` for unknown runtime values.
diff --git a/packages/acp-adapter/src/events-map.ts b/packages/acp-adapter/src/events-map.ts
index 37b4cc6ca..71a17ef45 100644
--- a/packages/acp-adapter/src/events-map.ts
+++ b/packages/acp-adapter/src/events-map.ts
@@ -56,6 +56,8 @@ export function assistantDeltaToSessionUpdate(
  *   belong on the JSON-RPC error channel). Returning `end_turn` keeps the
  *   client unblocked; the caller is expected to log the `error` payload
  *   separately so the failure is observable in the agent logs.
+ * Unknown runtime values also fall back to `end_turn` so a newer SDK
+ * reason cannot leak `undefined` onto the ACP wire.
  */
 export function turnEndReasonToStopReason(reason: TurnEndReason): AcpStopReason {
   switch (reason) {
@@ -65,6 +67,8 @@ export function turnEndReasonToStopReason(reason: TurnEndReason): AcpStopReason
       return 'cancelled';
     case 'failed':
       return 'end_turn';
+    default:
+      return 'end_turn';
   }
 }
 
diff --git a/packages/acp-adapter/test/events-map.test.ts b/packages/acp-adapter/test/events-map.test.ts
new file mode 100644
index 000000000..15637022c
--- /dev/null
+++ b/packages/acp-adapter/test/events-map.test.ts
@@ -0,0 +1,17 @@
+import { describe, expect, it } from 'vitest';
+
+import type { TurnEndReason } from '@moonshot-ai/kimi-code-sdk';
+
+import { turnEndReasonToStopReason } from '../src/events-map';
+
+describe('turnEndReasonToStopReason', () => {
+  it('maps known SDK turn-end reasons to ACP stop reasons', () => {
+    expect(turnEndReasonToStopReason('completed')).toBe('end_turn');
+    expect(turnEndReasonToStopReason('cancelled')).toBe('cancelled');
+    expect(turnEndReasonToStopReason('failed')).toBe('end_turn');
+  });
+
+  it('falls back to end_turn for unknown runtime reasons', () => {
+    expect(turnEndReasonToStopReason('interrupted' as TurnEndReason)).toBe('end_turn');
+  });
+});