diff --git a/packages/cli/src/index.ts b/packages/cli/src/index.ts
index 6909363..7d2af2a 100755
--- a/packages/cli/src/index.ts
+++ b/packages/cli/src/index.ts
@@ -1,5 +1,5 @@
 #!/usr/bin/env bun
-import { prompt, FileStorage, convertToATIF } from 'open-agent-sdk';
+import { prompt, FileStorage, convertToATIF, cleanupBackgroundProcesses } from 'open-agent-sdk';
 
 const args = process.argv.slice(2);
 
@@ -48,6 +48,7 @@ async function main() {
     ? undefined
     : new FileStorage(sessionDir ? { directory: sessionDir } : {});
 
+  let exitCode = 0;
   try {
     const result = await prompt(instruction!, {
       model: model!,
@@ -88,7 +89,11 @@ async function main() {
     } else {
       console.error(String(err));
     }
-    process.exit(1);
+    exitCode = 1;
+  } finally {
+    // Best-effort cleanup to avoid background command handles blocking process exit.
+    await cleanupBackgroundProcesses();
+    if (exitCode !== 0) process.exit(exitCode);
   }
 }
 
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 2141565..5fecc71 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -336,6 +336,7 @@ export {
   editTool,
   BashTool,
   bashTool,
+  cleanupBackgroundProcesses,
   GlobTool,
   globTool,
   GrepTool,
diff --git a/packages/core/src/tools/bash.ts b/packages/core/src/tools/bash.ts
index 26e11cc..fa73a2e 100644
--- a/packages/core/src/tools/bash.ts
+++ b/packages/core/src/tools/bash.ts
@@ -159,6 +159,11 @@ export class BashTool implements Tool<BashInput, BashOutput> {
           bgProcess.exitCode = code ?? -1;
         });
 
+        // Prevent background child handles from keeping the process alive.
+        child.unref();
+        (child.stdout as unknown as { unref?: () => void } | null)?.unref?.();
+        (child.stderr as unknown as { unref?: () => void } | null)?.unref?.();
+
         // Don't wait for completion
         resolve({
           output: `Command running in background with ID: ${shellId}`,
@@ -258,3 +263,47 @@ export const bashTool = new BashTool();
 export function getBackgroundProcess(shellId: string) {
   return backgroundProcesses.get(shellId);
 }
+
+/**
+ * Best-effort cleanup for any running background bash processes.
+ * Intended for process shutdown paths (e.g. CLI exit) to avoid hangs.
+ */
+export async function cleanupBackgroundProcesses(
+  forceKillAfterMs = 1000
+): Promise<void> {
+  const entries = Array.from(backgroundProcesses.values()).filter((p) => p.exitCode === null);
+
+  await Promise.all(
+    entries.map(
+      (bgProcess) =>
+        new Promise<void>((resolve) => {
+          if (bgProcess.exitCode !== null) {
+            resolve();
+            return;
+          }
+
+          let settled = false;
+          const done = () => {
+            if (settled) return;
+            settled = true;
+            clearTimeout(forceKillTimer);
+            resolve();
+          };
+
+          bgProcess.process.once('exit', (code) => {
+            bgProcess.exitCode = code ?? -1;
+            done();
+          });
+
+          bgProcess.process.kill('SIGTERM');
+
+          const forceKillTimer = setTimeout(() => {
+            if (bgProcess.exitCode === null) {
+              bgProcess.process.kill('SIGKILL');
+            }
+            done();
+          }, Math.max(1, forceKillAfterMs));
+        })
+    )
+  );
+}
diff --git a/packages/core/src/tools/registry.ts b/packages/core/src/tools/registry.ts
index e659117..a7acc02 100644
--- a/packages/core/src/tools/registry.ts
+++ b/packages/core/src/tools/registry.ts
@@ -91,7 +91,7 @@ export const defaultToolRegistry = createDefaultRegistry();
 export { readTool, ReadTool } from './read';
 export { writeTool, WriteTool } from './write';
 export { editTool, EditTool } from './edit';
-export { bashTool, BashTool } from './bash';
+export { bashTool, BashTool, cleanupBackgroundProcesses } from './bash';
 export { globTool, GlobTool } from './glob';
 export { grepTool, GrepTool } from './grep';
 export { taskListTool, TaskListTool } from './task-list';
diff --git a/packages/core/tests/tools/bash-enhanced.test.ts b/packages/core/tests/tools/bash-enhanced.test.ts
index 698945c..7fd7d24 100644
--- a/packages/core/tests/tools/bash-enhanced.test.ts
+++ b/packages/core/tests/tools/bash-enhanced.test.ts
@@ -3,7 +3,12 @@
  */
 
 import { describe, test, expect, beforeEach } from 'bun:test';
-import { BashTool, getBackgroundProcess } from '../../src/tools/bash';
+import {
+  BashTool,
+  getBackgroundProcess,
+  backgroundProcesses,
+  cleanupBackgroundProcesses,
+} from '../../src/tools/bash';
 import type { ToolContext } from '../../src/types/tools';
 
 describe('BashTool - Enhanced Background Process Tracking', () => {
@@ -11,6 +16,7 @@ describe('BashTool - Enhanced Background Process Tracking', () => {
   let context: ToolContext;
 
   beforeEach(() => {
+    backgroundProcesses.clear();
     tool = new BashTool();
     context = {
       cwd: process.cwd(),
@@ -142,4 +148,23 @@ describe('BashTool - Enhanced Background Process Tracking', () => {
     expect(process?.process).toBeDefined();
     expect(process?.process.pid).toBe(process?.pid);
   });
+
+  test('should cleanup running background processes', async () => {
+    const result = await tool.handler(
+      {
+        command: 'sleep 10',
+        run_in_background: true,
+      },
+      context
+    );
+
+    const shellId = result.shellId!;
+    const processBeforeCleanup = getBackgroundProcess(shellId);
+    expect(processBeforeCleanup?.exitCode).toBeNull();
+
+    await cleanupBackgroundProcesses(200);
+
+    const processAfterCleanup = getBackgroundProcess(shellId);
+    expect(processAfterCleanup?.exitCode).not.toBeNull();
+  });
 });