fix: 保证工具调用开始态可见

- 工具开始事件后让出一次有界绘制机会

- 覆盖快速工具调用的状态可见性测试

easyflow-ui-admin/app/src/views/ai/shared/agent-agui/client.test.ts

@@ -24,6 +24,7 @@ function sse(events: unknown[]) {
 describe('easyFlowAguiClient', () => {
   afterEach(() => {
     vi.unstubAllGlobals();
+    vi.useRealTimers();
   });
 
   it('trims outbound history, tools, context and state at the transport boundary', async () => {
@@ -200,6 +201,81 @@ describe('easyFlowAguiClient', () => {
     ).rejects.toBeInstanceOf(EasyFlowAguiProjectionError);
   });
 
+  it('yields a paint opportunity before consuming events after tool start', async () => {
+    vi.useFakeTimers();
+    let paintCallback: FrameRequestCallback | undefined;
+    vi.stubGlobal(
+      'requestAnimationFrame',
+      vi.fn((callback: FrameRequestCallback) => {
+        paintCallback = callback;
+        return 1;
+      }),
+    );
+    vi.stubGlobal(
+      'fetch',
+      vi.fn(async () =>
+        sse([
+          { runId: 'run-1', threadId: '101', type: EventType.RUN_STARTED },
+          {
+            runId: 'run-1',
+            threadId: '101',
+            toolCallId: 'tool-1',
+            toolCallName: 'write_text_file',
+            type: EventType.TOOL_CALL_START,
+          },
+          {
+            delta: '{}',
+            runId: 'run-1',
+            threadId: '101',
+            toolCallId: 'tool-1',
+            type: EventType.TOOL_CALL_ARGS,
+          },
+          {
+            runId: 'run-1',
+            threadId: '101',
+            toolCallId: 'tool-1',
+            type: EventType.TOOL_CALL_END,
+          },
+          {
+            content: 'done',
+            messageId: 'tool-result-1',
+            role: 'tool',
+            runId: 'run-1',
+            threadId: '101',
+            toolCallId: 'tool-1',
+            type: EventType.TOOL_CALL_RESULT,
+          },
+          {
+            runId: 'run-1',
+            threadId: '101',
+            type: EventType.RUN_FINISHED,
+          },
+        ]),
+      ),
+    );
+    const received: string[] = [];
+
+    const runPromise = new EasyFlowAguiClient().run({
+      onEvent: (event) => {
+        received.push(event.type);
+      },
+      threadId: '101',
+      url: '/api/v1/agent/1/agui/run',
+      userMessage: { content: '生成文件', id: 'user-1', role: 'user' },
+    });
+    await vi.advanceTimersByTimeAsync(0);
+
+    expect(received).toContain(EventType.TOOL_CALL_START);
+    expect(received).not.toContain(EventType.TOOL_CALL_RESULT);
+
+    paintCallback?.(0);
+    await vi.advanceTimersByTimeAsync(0);
+    await runPromise;
+
+    expect(received).toContain(EventType.TOOL_CALL_RESULT);
+    expect(received.at(-1)).toBe(EventType.RUN_FINISHED);
+  });
+
   it('replays a completed run from the server journal after refresh', async () => {
     vi.stubGlobal(
       'fetch',

easyflow-ui-admin/app/src/views/ai/shared/agent-agui/client.ts

@@ -29,6 +29,8 @@ interface ActiveAguiRun {
   abort: () => void;
 }
 
+const TOOL_START_PAINT_FALLBACK_MS = 50;
+
 /** 带 HTTP 状态码的 AG-UI 传输异常。 */
 export class EasyFlowAguiHttpError extends Error {
   constructor(
@@ -69,6 +71,36 @@ function toTransportJson<T>(value: T): T {
   return JSON.parse(JSON.stringify(value)) as T;
 }
 
+/**
+ * 在工具开始事件后让出一次页面绘制机会。
+ *
+ * <p>AG-UI 可能在同一批响应数据中连续送达工具开始和结果事件。Vue 虽已收到开始态，
+ * 浏览器仍可能在首次绘制前就将其覆盖为完成态。这里使用一帧回调并设置有界兜底，
+ * 既确保前台页面能展示“调用中”，也避免后台标签页暂停动画帧时阻塞事件流。</p>
+ *
+ * @returns 页面获得绘制机会后完成的 Promise
+ */
+function waitForToolStartPaint(): Promise<void> {
+  return new Promise((resolve) => {
+    let settled = false;
+    const complete = () => {
+      if (settled) return;
+      settled = true;
+      clearTimeout(fallbackTimer);
+      resolve();
+    };
+    const fallbackTimer = setTimeout(complete, TOOL_START_PAINT_FALLBACK_MS);
+    if (typeof globalThis.requestAnimationFrame !== 'function') {
+      setTimeout(complete, 0);
+      return;
+    }
+    globalThis.requestAnimationFrame(() => {
+      // requestAnimationFrame 回调发生在绘制前，再让出一个任务周期后继续消费后续事件。
+      setTimeout(complete, 0);
+    });
+  });
+}
+
 /**
  * EasyFlow 的无头 AG-UI 运行客户端。
  *
@@ -142,6 +174,9 @@ export class EasyFlowAguiClient {
         ) {
           terminalReceived = true;
         }
+        if (event.type === EventType.TOOL_CALL_START) {
+          await waitForToolStartPaint();
+        }
       }
       if (!activeRun.aborted && !terminalReceived) {
         throw new Error('Agent 事件流缺少终态，请重试');
@@ -198,6 +233,9 @@ export class EasyFlowAguiClient {
         if (Number.isSafeInteger(cursor) && cursor > 0) {
           options.onCursor?.(cursor);
         }
+        if (event.type === EventType.TOOL_CALL_START) {
+          await waitForToolStartPaint();
+        }
       }
       if (!terminalReceived) {
         if (activeRun.aborted) return;