test: lock down regressions surfaced by PR #5 review

Adds four regression tests that act as acceptance criteria for the
fixes shipped in PR #5 and the companion useChat fixes in this branch.

agent.test.ts:
- injectDeferralResults() + prompt() places the synthetic toolResult
  adjacent to its assistant block (verifies the documented "user typed
  instead of deciding" recovery pattern produces provider-valid order).

use-chat.test.ts:
- initialMessages with a paused tool call hydrates pendingDecisions.
- Two rapid synchronous send() calls both reach the outgoing body.
- Unmount aborts the in-flight fetch.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: yyyyaaa

packages/agent/__tests__/agent.test.ts

@@ -2,6 +2,7 @@ import {
   type AssistantMessage,
   type Context,
   createAssistantMessageEventStream,
+  injectDeferralResults,
   type Message,
   type ModelDescriptor,
   type ToolCallContent,
@@ -372,6 +373,53 @@ describe('@agentic-kit/agent — pausable tools', () => {
     expect(execute).not.toHaveBeenCalled();
   });
 
+  it('injectDeferralResults + prompt() places the synthetic toolResult adjacent to its assistant block', async () => {
+    const provider = createScriptedProvider({
+      responses: [pauseResponse(), finalResponse()],
+    });
+    const execute = jest.fn(async () => ({
+      content: [{ type: 'text' as const, text: 'should not run' }],
+    }));
+
+    const agent = new Agent({
+      initialState: { model: makeFakeModel() },
+      streamFn: provider.stream,
+    });
+    agent.setTools([makeApprovalTool(execute)]);
+
+    await agent.prompt('approve thing');
+
+    const withDeferrals = injectDeferralResults(agent.state.messages);
+    agent.replaceMessages(withDeferrals);
+
+    const typed: Message = {
+      role: 'user',
+      content: 'never mind',
+      timestamp: Date.now(),
+    };
+    await agent.prompt(typed);
+
+    const messages = agent.state.messages;
+    const assistantIdx = messages.findIndex(
+      (m) =>
+        m.role === 'assistant' &&
+        (m as AssistantMessage).content.some(
+          (b) => b.type === 'toolCall' && b.id === 'tool_1'
+        )
+    );
+    const toolResultIdx = messages.findIndex(
+      (m) => m.role === 'toolResult' && m.toolCallId === 'tool_1'
+    );
+    const typedIdx = messages.findIndex(
+      (m) => m.role === 'user' && m.content === 'never mind'
+    );
+
+    expect(assistantIdx).toBeGreaterThanOrEqual(0);
+    expect(toolResultIdx).toBe(assistantIdx + 1);
+    expect(typedIdx).toBe(toolResultIdx + 1);
+    expect(execute).not.toHaveBeenCalled();
+  });
+
   it('abort() while paused stops further work without throwing', async () => {
     const provider = createScriptedProvider({ responses: [pauseResponse()] });
 

packages/react/__tests__/use-chat.test.ts

@@ -54,6 +54,49 @@ describe('useChat', () => {
     expect(result.current.executingToolCallIds.size).toBe(0);
   });
 
+  it('hydrates pendingDecisions from initialMessages when a paused tool call is present', () => {
+    const initial: Message[] = [
+      makeUser('hi'),
+      makeAssistantWithToolCall('call_pending'),
+    ];
+
+    const { result } = renderHook(() =>
+      useChat({ api: '/chat', initialMessages: initial })
+    );
+
+    expect(result.current.pendingDecisions.has('call_pending')).toBe(true);
+    expect(result.current.pendingDecisions.get('call_pending')).toMatchObject({
+      toolCallId: 'call_pending',
+      toolName: 'echo',
+    });
+  });
+
+  it('send(): two rapid synchronous sends both reach the outgoing request body', async () => {
+    const final = makeFinalAssistant('ok');
+    const fetchFn = jest.fn(
+      async (_url: RequestInfo | URL, _init?: RequestInit): Promise<Response> =>
+        streamFromEvents([
+          { type: 'agent_start' },
+          { type: 'agent_end', messages: [makeUser('first'), makeUser('second'), final] },
+        ])
+    );
+
+    const { result } = renderHook(() => useChat({ api: '/chat', fetch: fetchFn }));
+
+    await act(async () => {
+      const p1 = result.current.send('first');
+      const p2 = result.current.send('second');
+      await Promise.allSettled([p1, p2]);
+    });
+
+    const lastInit = fetchFn.mock.calls.at(-1)![1] as RequestInit;
+    const sent = JSON.parse(lastInit.body as string);
+    const contents = sent.messages.map((m: Message) =>
+      typeof m.content === 'string' ? m.content : null
+    );
+    expect(contents).toEqual(['first', 'second']);
+  });
+
   it('sends, streams, and folds messages into the log', async () => {
     const final = makeFinalAssistant('world');
     const userEcho = makeUser('hello');
@@ -656,6 +699,36 @@ describe('useChat', () => {
       expect(result.current.isStreaming).toBe(false);
     });
 
+    it('unmount aborts the in-flight fetch', async () => {
+      let capturedSignal: AbortSignal | undefined;
+      const fetchFn = jest.fn(
+        (_url: RequestInfo | URL, init?: RequestInit): Promise<Response> => {
+          capturedSignal = init?.signal ?? undefined;
+          return new Promise<Response>((_resolve, reject) => {
+            init?.signal?.addEventListener('abort', () => {
+              const err = new Error('aborted');
+              err.name = 'AbortError';
+              reject(err);
+            });
+          });
+        }
+      );
+
+      const { result, unmount } = renderHook(() =>
+        useChat({ api: '/chat', fetch: fetchFn })
+      );
+
+      act(() => {
+        void result.current.send('hi');
+      });
+      await waitFor(() => expect(fetchFn).toHaveBeenCalled());
+      expect(capturedSignal?.aborted).toBe(false);
+
+      unmount();
+
+      expect(capturedSignal?.aborted).toBe(true);
+    });
+
     it('drops events that arrive after abort', async () => {
       let pushFn!: (event: AgentEvent) => void;
       let closeFn!: () => void;