feat(hooks): include final assistant message in Stop payload

.changeset/bright-hooks-report.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Include the final assistant message in Stop hook payloads.

docs/en/customization/hooks.md

@@ -100,7 +100,7 @@ Only **blockable events** (`PreToolUse`, `Stop`, `UserPromptSubmit`) have return
 | --- | --- | --- | --- |
 | `UserPromptSubmit` | The text submitted by the user | ✓ | Triggered when the user sends a message; returned text is appended to context; if blocked, the model is not called for this turn |
 | `PreToolUse` | Tool name | ✓ | Triggered before a tool call (before permission checks); the tool will not execute if blocked |
-| `Stop` | Empty string | ✓ | Triggered when the model is about to end the current turn; if blocked, a message can be appended to let the model continue |
+| `Stop` | Empty string | ✓ | Triggered when the model is about to end the current turn; the payload includes the final assistant text as `last_assistant_message`; if blocked, a message can be appended to let the model continue |
 | `PostToolUse` | Tool name | — | Triggered after a tool executes successfully (observation only) |
 | `PostToolUseFailure` | Tool name | — | Triggered after a tool fails or is blocked (observation only) |
 | `PermissionRequest` | Tool name | — | Triggered just before waiting for user approval (observation only) |

docs/zh/customization/hooks.md

@@ -100,7 +100,7 @@ Hook 命令的工作目录是当前会话的项目目录。非 Windows 平台上
 | --- | --- | --- | --- |
 | `UserPromptSubmit` | 用户提交的文本内容 | ✓ | 用户发送消息时触发；返回文本会附加到上下文；若阻断，本轮不调用模型 |
 | `PreToolUse` | 工具名 | ✓ | 工具调用前触发（权限检查前）；阻断后工具不会执行 |
-| `Stop` | 空字符串 | ✓ | 模型准备结束本轮时触发；阻断后可追加一条消息让模型继续 |
+| `Stop` | 空字符串 | ✓ | 模型准备结束本轮时触发；payload 通过 `last_assistant_message` 提供最后一条助手文本；阻断后可追加一条消息让模型继续 |
 | `PostToolUse` | 工具名 | — | 工具成功执行后触发（观察用） |
 | `PostToolUseFailure` | 工具名 | — | 工具失败或被阻断后触发（观察用） |
 | `PermissionRequest` | 工具名 | — | 即将等待用户审批前触发（观察用） |

packages/agent-core-v2/docs/state-manifest.d.ts

@@ -1004,7 +1004,7 @@ export interface AgentStateSnapshot {
   'llmRequester.lastConfigLogSignature': string | undefined;
   'llmRequester.mediaDegradedTurns': Set<number>;
   'llmRequester.mediaStrippedTurns': Map<number, /* MediaStripSnapshot — packages/agent-core-v2/src/agent/contextProjector/contextProjector.ts */ {
-    readonly "__@mediaStripSnapshotBrand@2376": undefined;
+    readonly "__@mediaStripSnapshotBrand@2378": undefined;
   }>;
   'llmRequester.turnConfigs': Map<number, /* TurnRequestConfig — packages/agent-core-v2/src/agent/llmRequester/llmRequesterService.ts */ {
     readonly resolved: /* ProfileModelContext — packages/agent-core-v2/src/agent/profile/profile.ts */ {

packages/agent-core-v2/src/agent/externalHooks/externalHooksService.ts

@@ -44,6 +44,7 @@ import type { ResolvedToolExecutionHookContext, ToolDidExecuteContext } from '#/
 import { denyToolExecution } from '#/agent/toolExecutor/beforeToolExecuteEvent';
 import { IAgentToolExecutorService } from '#/agent/toolExecutor/toolExecutor';
 import { toKimiErrorPayload } from '#/errors';
+import { extractText } from '#/kosong/contract/message';
 import { ISessionContext } from '#/session/sessionContext/sessionContext';
 
 import { IAgentExternalHooksService } from './externalHooks';
@@ -352,11 +353,15 @@ export class AgentExternalHooksService extends Disposable implements IAgentExter
   private async runStop(ctx: AfterStepContext): Promise<string | undefined> {
     ctx.signal.throwIfAborted();
     if (this.stopHookContinuationUsed) return undefined;
+    const lastAssistant = this.context.get().findLast((entry) => entry.role === 'assistant');
 
     const block = await this.runner.triggerBlock('Stop', {
       signal: ctx.signal,
       sessionId: this.sessionContext.sessionId,
-      inputData: { stopHookActive: false },
+      inputData: {
+        stopHookActive: false,
+        last_assistant_message: lastAssistant === undefined ? '' : extractText(lastAssistant),
+      },
     });
     ctx.signal.throwIfAborted();
     return block?.reason;

packages/agent-core-v2/test/app/externalHooksRunner/integration.test.ts

@@ -281,6 +281,12 @@ describe('IExternalHooksRunnerService integration', () => {
       ix.set(IAgentExternalHooksService, new SyncDescriptor(AgentExternalHooksService));
       ix.get(IAgentExternalHooksService);
       const eventBus = ix.get(IEventBus);
+      const finalAssistantMessage = 'release is ready';
+      context.append({
+        role: 'assistant',
+        content: [{ type: 'text', text: finalAssistantMessage }],
+        toolCalls: [],
+      });
 
       const signal = new AbortController().signal;
       const filtered: AfterStepContext = {
@@ -290,7 +296,7 @@ describe('IExternalHooksRunnerService integration', () => {
       await loop.hooks.onDidFinishStep.run(filtered);
       expect(loop.hasPendingRequests()).toBe(false);
       expect(stopInputs).toEqual([]);
-      expect(context.messages).toEqual([]);
+      expect(context.messages).toHaveLength(1);
 
       const first = makeAfterStep(signal);
       await loop.hooks.onDidFinishStep.run(first);
@@ -307,7 +313,12 @@ describe('IExternalHooksRunnerService integration', () => {
       const second = makeAfterStep(signal);
       await loop.hooks.onDidFinishStep.run(second);
       expect(loop.hasPendingRequests()).toBe(false);
-      expect(stopInputs).toEqual([{ stopHookActive: false }]);
+      expect(stopInputs).toEqual([
+        {
+          stopHookActive: false,
+          last_assistant_message: finalAssistantMessage,
+        },
+      ]);
 
       eventBus.publish({
         type: 'turn.ended',
@@ -327,7 +338,16 @@ describe('IExternalHooksRunnerService integration', () => {
         }),
       );
       expect(loop.drainNextBatch(context)).toBeDefined();
-      expect(stopInputs).toEqual([{ stopHookActive: false }, { stopHookActive: false }]);
+      expect(stopInputs).toEqual([
+        {
+          stopHookActive: false,
+          last_assistant_message: finalAssistantMessage,
+        },
+        {
+          stopHookActive: false,
+          last_assistant_message: finalAssistantMessage,
+        },
+      ]);
     } finally {
       ix?.dispose();
       disposables.dispose();

packages/agent-core/src/agent/turn/index.ts

@@ -8,6 +8,7 @@ import {
   APIProviderQuotaExhaustedError,
   APIStatusError,
   APITimeoutError,
+  extractText,
   inputTotal,
   isContextOverflowStatusError,
   type ContentPart,
@@ -942,9 +943,16 @@ export class TurnFlow {
               // 3. The external Stop hook gets exactly one continuation; the cap
               //    is intentionally separate from (and does not cap) goal mode.
               if (!stopHookContinuationUsed) {
+                const lastAssistant = this.agent.context.history.findLast(
+                  (entry) => entry.role === 'assistant',
+                );
                 const stopBlock = await this.agent.hooks?.triggerBlock('Stop', {
                   signal,
-                  inputData: { stopHookActive: stopHookContinuationUsed },
+                  inputData: {
+                    stopHookActive: stopHookContinuationUsed,
+                    last_assistant_message:
+                      lastAssistant === undefined ? '' : extractText(lastAssistant),
+                  },
                 });
                 signal.throwIfAborted();
                 if (stopBlock !== undefined) {

packages/agent-core/test/agent/turn.test.ts

@@ -1466,6 +1466,37 @@ describe('Agent turn flow', () => {
     expect(JSON.stringify(ctx.agent.context.data().history)).toContain('Second answer.');
   });
 
+  it('includes the final assistant message in the Stop hook payload', async () => {
+    const script = [
+      "let input='';",
+      "process.stdin.on('data',chunk=>input+=chunk);",
+      "process.stdin.on('end',()=>{",
+      'const payload=JSON.parse(input);',
+      "process.stdout.write(JSON.stringify({hookSpecificOutput:{permissionDecision:'deny',permissionDecisionReason:payload.last_assistant_message}}));",
+      '});',
+    ].join('');
+    const hookEngine = new HookEngine([
+      {
+        event: 'Stop',
+        command: `node -e ${JSON.stringify(script)}`,
+      },
+    ]);
+    const ctx = testAgent({ hookEngine });
+    ctx.configure();
+    ctx.mockNextResponse({ type: 'text', text: 'Final answer for the hook.' });
+    ctx.mockNextResponse({ type: 'text', text: 'Continued after the hook.' });
+
+    await ctx.rpc.prompt({ input: [{ type: 'text', text: 'hello' }] });
+    await ctx.untilTurnEnd();
+
+    expect(ctx.agent.context.data().history).toContainEqual({
+      role: 'user',
+      content: [{ type: 'text', text: 'Final answer for the hook.' }],
+      toolCalls: [],
+      origin: { kind: 'system_trigger', name: 'stop_hook' },
+    });
+  });
+
   it('cancels while waiting for a Stop hook', async () => {
     const dir = mkdtempSync(join(tmpdir(), 'kimi-stop-hook-'));
     const marker = join(dir, 'started');