fix: improve windows background process handling and cleanup

packages/core/src/services/shellExecutionService.test.ts

@@ -589,7 +589,7 @@ describe('ShellExecutionService child_process fallback', () => {
       expect(result.error).toBeNull();
       expect(result.aborted).toBe(false);
       expect(result.output).toBe('file1.txt\na warning');
-      expect(handle.pid).toBe(undefined);
+      expect(handle.pid).toBe(12345);
 
       expect(onOutputEventMock).toHaveBeenCalledWith({
         type: 'data',

packages/core/src/services/shellExecutionService.ts

@@ -7,7 +7,7 @@
 import stripAnsi from 'strip-ansi';
 import type { PtyImplementation } from '../utils/getPty.js';
 import { getPty } from '../utils/getPty.js';
-import { spawn as cpSpawn } from 'node:child_process';
+import { spawn as cpSpawn, spawnSync } from 'node:child_process';
 import { TextDecoder } from 'node:util';
 import os from 'node:os';
 import type { IPty } from '@lydell/node-pty';
@@ -106,6 +106,52 @@ const getFullBufferText = (terminal: pkg.Terminal): string => {
 
 export class ShellExecutionService {
   private static activePtys = new Map<number, ActivePty>();
+  private static activeChildProcesses = new Set<number>();
+
+  static cleanup() {
+    // Cleanup PTYs
+    for (const [pid, pty] of this.activePtys) {
+      try {
+        if (os.platform() === 'win32') {
+          pty.ptyProcess.kill();
+        } else {
+          process.kill(-pid, 'SIGKILL');
+        }
+      } catch {
+        // ignore
+      }
+    }
+
+    // Cleanup child processes
+    if (os.platform() === 'win32') {
+      if (this.activeChildProcesses.size > 0) {
+        try {
+          const args = ['/f', '/t'];
+          for (const pid of this.activeChildProcesses) {
+            args.push('/pid', pid.toString());
+          }
+          spawnSync('taskkill', args);
+        } catch {
+          // ignore
+        }
+      }
+    } else {
+      for (const pid of this.activeChildProcesses) {
+        try {
+          process.kill(-pid, 'SIGKILL');
+        } catch {
+          // ignore
+        }
+      }
+    }
+  }
+
+  static {
+    process.on('exit', () => {
+      ShellExecutionService.cleanup();
+    });
+  }
+
   /**
    * Executes a shell command using `node-pty`, capturing all output and lifecycle events.
    *
@@ -281,9 +327,13 @@ export class ShellExecutionService {
 
         abortSignal.addEventListener('abort', abortHandler, { once: true });
 
+        if (child.pid) {
+          this.activeChildProcesses.add(child.pid);
+        }
+
         child.on('exit', (code, signal) => {
           if (child.pid) {
-            this.activePtys.delete(child.pid);
+            this.activeChildProcesses.delete(child.pid);
           }
           handleExit(code, signal);
         });
@@ -310,7 +360,7 @@ export class ShellExecutionService {
         }
       });
 
-      return { pid: undefined, result };
+      return { pid: child.pid, result };
     } catch (e) {
       const error = e as Error;
       return {

packages/core/src/tools/shell.test.ts

@@ -210,7 +210,7 @@ describe('ShellTool', () => {
         wrappedCommand,
         '/test/dir',
         expect.any(Function),
-        mockAbortSignal,
+        expect.any(AbortSignal),
         false,
         {},
       );
@@ -237,7 +237,7 @@ describe('ShellTool', () => {
         wrappedCommand,
         expect.any(String),
         expect.any(Function),
-        mockAbortSignal,
+        expect.any(AbortSignal),
         false,
         {},
       );
@@ -262,7 +262,7 @@ describe('ShellTool', () => {
         wrappedCommand,
         expect.any(String),
         expect.any(Function),
-        mockAbortSignal,
+        expect.any(AbortSignal),
         false,
         {},
       );
@@ -287,7 +287,7 @@ describe('ShellTool', () => {
         wrappedCommand,
         expect.any(String),
         expect.any(Function),
-        mockAbortSignal,
+        expect.any(AbortSignal),
         false,
         {},
       );
@@ -312,7 +312,7 @@ describe('ShellTool', () => {
         wrappedCommand,
         '/test/dir/subdir',
         expect.any(Function),
-        mockAbortSignal,
+        expect.any(AbortSignal),
         false,
         {},
       );
@@ -340,7 +340,7 @@ describe('ShellTool', () => {
         'dir',
         '/test/dir',
         expect.any(Function),
-        mockAbortSignal,
+        expect.any(AbortSignal),
         false,
         {},
       );
@@ -433,7 +433,7 @@ describe('ShellTool', () => {
       expect(summarizer.summarizeToolOutput).toHaveBeenCalledWith(
         expect.any(String),
         mockConfig.getGeminiClient(),
-        mockAbortSignal,
+        expect.any(AbortSignal),
         1000,
       );
       expect(result.llmContent).toBe('summarized output');
@@ -542,7 +542,7 @@ describe('ShellTool', () => {
           ),
           expect.any(String),
           expect.any(Function),
-          mockAbortSignal,
+          expect.any(AbortSignal),
           false,
           {},
         );
@@ -572,7 +572,7 @@ describe('ShellTool', () => {
           ),
           expect.any(String),
           expect.any(Function),
-          mockAbortSignal,
+          expect.any(AbortSignal),
           false,
           {},
         );
@@ -602,7 +602,7 @@ describe('ShellTool', () => {
           ),
           expect.any(String),
           expect.any(Function),
-          mockAbortSignal,
+          expect.any(AbortSignal),
           false,
           {},
         );
@@ -631,7 +631,7 @@ describe('ShellTool', () => {
           expect.stringContaining('npm install'),
           expect.any(String),
           expect.any(Function),
-          mockAbortSignal,
+          expect.any(AbortSignal),
           false,
           {},
         );
@@ -660,7 +660,7 @@ describe('ShellTool', () => {
           expect.stringContaining('git commit'),
           expect.any(String),
           expect.any(Function),
-          mockAbortSignal,
+          expect.any(AbortSignal),
           false,
           {},
         );
@@ -690,7 +690,7 @@ describe('ShellTool', () => {
           ),
           expect.any(String),
           expect.any(Function),
-          mockAbortSignal,
+          expect.any(AbortSignal),
           false,
           {},
         );
@@ -726,7 +726,7 @@ describe('ShellTool', () => {
           expect.stringContaining('git commit -m "Initial commit"'),
           expect.any(String),
           expect.any(Function),
-          mockAbortSignal,
+          expect.any(AbortSignal),
           false,
           {},
         );
@@ -763,7 +763,7 @@ describe('ShellTool', () => {
           ),
           expect.any(String),
           expect.any(Function),
-          mockAbortSignal,
+          expect.any(AbortSignal),
           false,
           {},
         );
@@ -831,4 +831,68 @@ describe('ShellTool', () => {
       expect(shellTool.description).toMatchSnapshot();
     });
   });
+
+  describe('Windows background execution', () => {
+    it('should clean up trailing ampersand on Windows for background tasks', async () => {
+      vi.mocked(os.platform).mockReturnValue('win32');
+      const mockAbortSignal = new AbortController().signal;
+
+      const invocation = shellTool.build({
+        command: 'npm start &',
+        is_background: true,
+      });
+
+      const promise = invocation.execute(mockAbortSignal);
+
+      // Simulate immediate success (process started)
+      resolveExecutionPromise({
+        rawOutput: Buffer.from(''),
+        output: '',
+        exitCode: 0,
+        signal: null,
+        error: null,
+        aborted: false,
+        pid: 12345,
+        executionMethod: 'child_process',
+      });
+
+      await promise;
+
+      expect(mockShellExecutionService).toHaveBeenCalledWith(
+        'npm start',
+        expect.any(String),
+        expect.any(Function),
+        expect.any(AbortSignal),
+        false,
+        {},
+      );
+    });
+
+    it('should detect immediate failure in Windows background task', async () => {
+      vi.mocked(os.platform).mockReturnValue('win32');
+      const mockAbortSignal = new AbortController().signal;
+
+      const invocation = shellTool.build({
+        command: 'invalid_command',
+        is_background: true,
+      });
+
+      const promise = invocation.execute(mockAbortSignal);
+
+      // Wait a tick to ensure mockShellOutputCallback is assigned
+      await new Promise((resolve) => setTimeout(resolve, 0));
+
+      if (mockShellOutputCallback) {
+        mockShellOutputCallback({
+          type: 'data',
+          chunk:
+            "'invalid_command' is not recognized as an internal or external command,\r\noperable program or batch file.\r\n",
+        });
+      }
+
+      const result = await promise;
+      expect(result.error).toBeDefined();
+      expect(result.llmContent).toContain('Command failed to start');
+    });
+  });
 });