diff --git a/packages/a2a-server/src/agent/task-event-driven.test.ts b/packages/a2a-server/src/agent/task-event-driven.test.ts
index 86436fa811..5fc548a8f4 100644
--- a/packages/a2a-server/src/agent/task-event-driven.test.ts
+++ b/packages/a2a-server/src/agent/task-event-driven.test.ts
@@ -66,6 +66,7 @@ describe('Task Event-Driven Scheduler', () => {
     handler({
       type: MessageBusType.TOOL_CALLS_UPDATE,
       toolCalls: [toolCall],
+      schedulerId: 'task-id',
     });
 
     expect(mockEventBus.publish).toHaveBeenCalledWith(
@@ -106,6 +107,7 @@ describe('Task Event-Driven Scheduler', () => {
     handler({
       type: MessageBusType.TOOL_CALLS_UPDATE,
       toolCalls: [toolCall],
+      schedulerId: 'task-id',
     });
 
     // Simulate A2A client confirmation
@@ -148,7 +150,11 @@ describe('Task Event-Driven Scheduler', () => {
     const handler = (messageBus.subscribe as Mock).mock.calls.find(
       (call: unknown[]) => call[0] === MessageBusType.TOOL_CALLS_UPDATE,
     )?.[1];
-    handler({ type: MessageBusType.TOOL_CALLS_UPDATE, toolCalls: [toolCall] });
+    handler({
+      type: MessageBusType.TOOL_CALLS_UPDATE,
+      toolCalls: [toolCall],
+      schedulerId: 'task-id',
+    });
 
     // Simulate Rejection (Cancel)
     const handled = await (
@@ -174,7 +180,11 @@ describe('Task Event-Driven Scheduler', () => {
       correlationId: 'corr-2',
       confirmationDetails: { type: 'info', title: 'test', prompt: 'test' },
     };
-    handler({ type: MessageBusType.TOOL_CALLS_UPDATE, toolCalls: [toolCall2] });
+    handler({
+      type: MessageBusType.TOOL_CALLS_UPDATE,
+      toolCalls: [toolCall2],
+      schedulerId: 'task-id',
+    });
 
     // Simulate ModifyWithEditor
     const handled2 = await (
@@ -215,7 +225,11 @@ describe('Task Event-Driven Scheduler', () => {
     const handler = (messageBus.subscribe as Mock).mock.calls.find(
       (call: unknown[]) => call[0] === MessageBusType.TOOL_CALLS_UPDATE,
     )?.[1];
-    handler({ type: MessageBusType.TOOL_CALLS_UPDATE, toolCalls: [toolCall] });
+    handler({
+      type: MessageBusType.TOOL_CALLS_UPDATE,
+      toolCalls: [toolCall],
+      schedulerId: 'task-id',
+    });
 
     // Simulate ProceedOnce for MCP
     const handled = await (
@@ -255,7 +269,11 @@ describe('Task Event-Driven Scheduler', () => {
     const handler = (messageBus.subscribe as Mock).mock.calls.find(
       (call: unknown[]) => call[0] === MessageBusType.TOOL_CALLS_UPDATE,
     )?.[1];
-    handler({ type: MessageBusType.TOOL_CALLS_UPDATE, toolCalls: [toolCall] });
+    handler({
+      type: MessageBusType.TOOL_CALLS_UPDATE,
+      toolCalls: [toolCall],
+      schedulerId: 'task-id',
+    });
 
     const handled = await (
       task as unknown as {
@@ -294,7 +312,11 @@ describe('Task Event-Driven Scheduler', () => {
     const handler = (messageBus.subscribe as Mock).mock.calls.find(
       (call: unknown[]) => call[0] === MessageBusType.TOOL_CALLS_UPDATE,
     )?.[1];
-    handler({ type: MessageBusType.TOOL_CALLS_UPDATE, toolCalls: [toolCall] });
+    handler({
+      type: MessageBusType.TOOL_CALLS_UPDATE,
+      toolCalls: [toolCall],
+      schedulerId: 'task-id',
+    });
 
     const handled = await (
       task as unknown as {
@@ -333,7 +355,11 @@ describe('Task Event-Driven Scheduler', () => {
     const handler = (messageBus.subscribe as Mock).mock.calls.find(
       (call: unknown[]) => call[0] === MessageBusType.TOOL_CALLS_UPDATE,
     )?.[1];
-    handler({ type: MessageBusType.TOOL_CALLS_UPDATE, toolCalls: [toolCall] });
+    handler({
+      type: MessageBusType.TOOL_CALLS_UPDATE,
+      toolCalls: [toolCall],
+      schedulerId: 'task-id',
+    });
 
     const handled = await (
       task as unknown as {
@@ -376,7 +402,11 @@ describe('Task Event-Driven Scheduler', () => {
     const handler = (yoloMessageBus.subscribe as Mock).mock.calls.find(
       (call: unknown[]) => call[0] === MessageBusType.TOOL_CALLS_UPDATE,
     )?.[1];
-    handler({ type: MessageBusType.TOOL_CALLS_UPDATE, toolCalls: [toolCall] });
+    handler({
+      type: MessageBusType.TOOL_CALLS_UPDATE,
+      toolCalls: [toolCall],
+      schedulerId: 'task-id',
+    });
 
     // Should NOT auto-publish ProceedOnce anymore, because PolicyEngine handles it directly
     expect(yoloMessageBus.publish).not.toHaveBeenCalledWith(
@@ -419,6 +449,7 @@ describe('Task Event-Driven Scheduler', () => {
     handler({
       type: MessageBusType.TOOL_CALLS_UPDATE,
       toolCalls: [toolCall],
+      schedulerId: 'task-id',
     });
 
     // Should publish artifact update for output
@@ -453,7 +484,11 @@ describe('Task Event-Driven Scheduler', () => {
     const handler = (messageBus.subscribe as Mock).mock.calls.find(
       (call: unknown[]) => call[0] === MessageBusType.TOOL_CALLS_UPDATE,
     )?.[1];
-    handler({ type: MessageBusType.TOOL_CALLS_UPDATE, toolCalls: [toolCall] });
+    handler({
+      type: MessageBusType.TOOL_CALLS_UPDATE,
+      toolCalls: [toolCall],
+      schedulerId: 'task-id',
+    });
 
     // The tool should be complete and registered appropriately, eventually
     // triggering the toolCompletionPromise resolution when all clear.
@@ -533,6 +568,7 @@ describe('Task Event-Driven Scheduler', () => {
     handler({
       type: MessageBusType.TOOL_CALLS_UPDATE,
       toolCalls: [toolCall1, toolCall2],
+      schedulerId: 'task-id',
     });
 
     // Confirm first tool call
@@ -600,6 +636,7 @@ describe('Task Event-Driven Scheduler', () => {
     handler({
       type: MessageBusType.TOOL_CALLS_UPDATE,
       toolCalls: [toolCall1, toolCall2],
+      schedulerId: 'task-id',
     });
 
     // Should NOT transition to input-required yet
@@ -621,6 +658,7 @@ describe('Task Event-Driven Scheduler', () => {
     handler({
       type: MessageBusType.TOOL_CALLS_UPDATE,
       toolCalls: [toolCall1Complete, toolCall2],
+      schedulerId: 'task-id',
     });
 
     // Now it should transition
diff --git a/packages/a2a-server/src/agent/task.test.ts b/packages/a2a-server/src/agent/task.test.ts
index 26039ae3aa..27e6c28fed 100644
--- a/packages/a2a-server/src/agent/task.test.ts
+++ b/packages/a2a-server/src/agent/task.test.ts
@@ -460,4 +460,110 @@ describe('Task', () => {
       expect(task.currentPromptId).toBe(expectedPromptId2);
     });
   });
+
+  describe('Race Condition Fix', () => {
+    const mockConfig = createMockConfig();
+    const mockEventBus: ExecutionEventBus = {
+      publish: vi.fn(),
+      on: vi.fn(),
+      off: vi.fn(),
+      once: vi.fn(),
+      removeAllListeners: vi.fn(),
+      finished: vi.fn(),
+    };
+
+    beforeEach(() => {
+      vi.clearAllMocks();
+    });
+
+    it('should NOT transition to input-required if a tool is still validating', async () => {
+      // @ts-expect-error - Calling private constructor
+      const task = new Task(
+        'task-id',
+        'context-id',
+        mockConfig as Config,
+        mockEventBus,
+      );
+
+      // Manually register two tool calls
+      task['_registerToolCall']('tool-1', 'awaiting_approval');
+      task['_registerToolCall']('tool-2', 'validating');
+
+      // Call checkInputRequiredState (private)
+      task['checkInputRequiredState']();
+
+      // Verify task state did NOT change to input-required
+      expect(task.taskState).not.toBe('input-required');
+      expect(mockEventBus.publish).not.toHaveBeenCalledWith(
+        expect.objectContaining({
+          status: expect.objectContaining({ state: 'input-required' }),
+        }),
+      );
+    });
+
+    it('should transition to input-required if all active tools are awaiting approval', async () => {
+      // @ts-expect-error - Calling private constructor
+      const task = new Task(
+        'task-id',
+        'context-id',
+        mockConfig as Config,
+        mockEventBus,
+      );
+
+      // Transition from submitted to working first to simulate normal flow
+      task.taskState = 'working';
+
+      // Manually register tool calls
+      task['_registerToolCall']('tool-1', 'awaiting_approval');
+
+      // Call checkInputRequiredState
+      task['checkInputRequiredState']();
+
+      // Verify task state changed to input-required
+      expect(task.taskState).toBe('input-required');
+      expect(mockEventBus.publish).toHaveBeenCalledWith(
+        expect.objectContaining({
+          status: expect.objectContaining({ state: 'input-required' }),
+        }),
+      );
+    });
+
+    it('handleEventDrivenToolCallsUpdate should ignore events for other schedulers', async () => {
+      // @ts-expect-error - Calling private constructor
+      const task = new Task(
+        'task-id',
+        'context-id',
+        mockConfig as Config,
+        mockEventBus,
+      );
+
+      const handleEventDrivenToolCallSpy = vi.spyOn(
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        task as any,
+        'handleEventDrivenToolCall',
+      );
+
+      const otherEvent = {
+        type: 'tool-calls-update',
+        toolCalls: [{ request: { callId: '1' }, status: 'executing' }],
+        schedulerId: 'other-task-id',
+      };
+
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      task['handleEventDrivenToolCallsUpdate'](otherEvent as any);
+
+      expect(handleEventDrivenToolCallSpy).not.toHaveBeenCalled();
+
+      const ownEvent = {
+        type: 'tool-calls-update',
+        toolCalls: [{ request: { callId: '1' }, status: 'executing' }],
+        schedulerId: 'task-id',
+      };
+
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      task['handleEventDrivenToolCallsUpdate'](ownEvent as any);
+
+      expect(handleEventDrivenToolCallSpy).toHaveBeenCalled();
+    });
+  });
 });
diff --git a/packages/a2a-server/src/agent/task.ts b/packages/a2a-server/src/agent/task.ts
index a76054263f..6e87a033dd 100644
--- a/packages/a2a-server/src/agent/task.ts
+++ b/packages/a2a-server/src/agent/task.ts
@@ -413,7 +413,10 @@ export class Task {
   private handleEventDrivenToolCallsUpdate(
     event: ToolCallsUpdateMessage,
   ): void {
-    if (event.type !== MessageBusType.TOOL_CALLS_UPDATE) {
+    if (
+      event.type !== MessageBusType.TOOL_CALLS_UPDATE ||
+      event.schedulerId !== this.id
+    ) {
       return;
     }
 
@@ -508,7 +511,11 @@ export class Task {
     let isExecuting = false;
 
     for (const [callId, status] of this.pendingToolCalls.entries()) {
-      if (status === 'executing' || status === 'scheduled') {
+      if (
+        status === 'executing' ||
+        status === 'scheduled' ||
+        status === 'validating'
+      ) {
         isExecuting = true;
       } else if (
         status === 'awaiting_approval' &&
diff --git a/packages/a2a-server/src/http/app.test.ts b/packages/a2a-server/src/http/app.test.ts
index 4a883992b5..ac4568ba3d 100644
--- a/packages/a2a-server/src/http/app.test.ts
+++ b/packages/a2a-server/src/http/app.test.ts
@@ -381,11 +381,11 @@ describe('E2E Tests', () => {
     ]);
 
     // 6. Tool 1 is awaiting approval.
-    const toolCallAwaitEvent = events[5].result as TaskStatusUpdateEvent;
-    expect(toolCallAwaitEvent.metadata?.['coderAgent']).toMatchObject({
+    const toolCallAwaitEvent1 = events[5].result as TaskStatusUpdateEvent;
+    expect(toolCallAwaitEvent1.metadata?.['coderAgent']).toMatchObject({
       kind: 'tool-call-confirmation',
     });
-    expect(toolCallAwaitEvent.status.message?.parts).toMatchObject([
+    expect(toolCallAwaitEvent1.status.message?.parts).toMatchObject([
       {
         data: {
           request: { callId: 'test-call-id-1' },
@@ -394,14 +394,28 @@ describe('E2E Tests', () => {
       },
     ]);
 
-    // 7. The final event is "input-required".
-    const finalEvent = events[6].result as TaskStatusUpdateEvent;
+    // 7. Tool 2 is awaiting approval.
+    const toolCallAwaitEvent2 = events[6].result as TaskStatusUpdateEvent;
+    expect(toolCallAwaitEvent2.metadata?.['coderAgent']).toMatchObject({
+      kind: 'tool-call-confirmation',
+    });
+    expect(toolCallAwaitEvent2.status.message?.parts).toMatchObject([
+      {
+        data: {
+          request: { callId: 'test-call-id-2' },
+          status: 'awaiting_approval',
+        },
+      },
+    ]);
+
+    // 8. The final event is "input-required".
+    const finalEvent = events[7].result as TaskStatusUpdateEvent;
     expect(finalEvent.final).toBe(true);
     expect(finalEvent.status.state).toBe('input-required');
 
     // The scheduler now waits for approval, so no more events are sent.
     assertUniqueFinalEventIsLast(events);
-    expect(events.length).toBe(7);
+    expect(events.length).toBe(8);
   });
 
   it('should handle multiple tool calls sequentially in YOLO mode', async () => {