diff --git a/src/plugin/pty/session-lifecycle.ts b/src/plugin/pty/session-lifecycle.ts
index 6927998..8f30e62 100644
--- a/src/plugin/pty/session-lifecycle.ts
+++ b/src/plugin/pty/session-lifecycle.ts
@@ -46,22 +46,8 @@ export class SessionLifecycleManager {
     const timeoutMs = session.timeoutSeconds * 1000
 
     const timeoutHandle = setTimeout(() => {
-      this.sessionTimeouts.delete(session.id)
-
-      const currentSession = this.sessions.get(session.id)
-      if (!currentSession || currentSession.status !== 'running') {
-        return
-      }
-
-      // Persist the timeout reason before reusing the regular kill flow.
-      currentSession.timedOut = true
-      currentSession.status = 'killing'
-
-      try {
-        currentSession.process?.kill()
-      } catch {
-        // Ignore kill errors
-      }
+      session.timedOut = true
+      this.kill(session.id)
     }, timeoutMs)
 
     this.sessionTimeouts.set(session.id, timeoutHandle)
@@ -121,6 +107,11 @@ export class SessionLifecycleManager {
     })
 
     session.process?.onExit(({ exitCode, signal }) => {
+      // Releasing the native PTY can emit onExit again synchronously.
+      if (session.exitAt) {
+        return
+      }
+
       this.clearSessionTimeout(session.id)
 
       // Flush any remaining incomplete line in the buffer
@@ -136,6 +127,11 @@ export class SessionLifecycleManager {
       // When the process stopped, so a reader can report how long it ran: the
       // buffer keeps the output but nothing else records the end.
       session.exitAt = new Date()
+      try {
+        session.process?.kill()
+      } catch {
+        // Ignore kill errors
+      }
       onExit(session, exitCode)
     })
   }
@@ -178,16 +174,12 @@ export class SessionLifecycleManager {
     return true
   }
 
-  private clearAllSessionsInternal(): void {
+  clearAllSessions(): void {
     for (const id of [...this.sessions.keys()]) {
       this.kill(id, true)
     }
   }
 
-  clearAllSessions(): void {
-    this.clearAllSessionsInternal()
-  }
-
   cleanupBySession(parentSessionId: string): void {
     for (const [id, session] of this.sessions) {
       if (session.parentSessionId === parentSessionId) {
diff --git a/test/session-lifecycle.test.ts b/test/session-lifecycle.test.ts
new file mode 100644
index 0000000..f6c9c14
--- /dev/null
+++ b/test/session-lifecycle.test.ts
@@ -0,0 +1,21 @@
+import { expect, it, mock, spyOn } from 'bun:test'
+import { SessionLifecycleManager } from '../src/plugin/pty/session-lifecycle.ts'
+
+it('releases the native PTY on natural exit without duplicating the exit callback', async () => {
+  const manager = new SessionLifecycleManager()
+  const { promise: exited, resolve } = Promise.withResolvers<void>()
+  const onExit = mock(() => resolve())
+  const info = manager.spawn(
+    { command: 'sh', args: ['-c', 'exit 3'], parentSessionId: 'test-session' },
+    () => {},
+    onExit
+  )
+  const session = manager.getSession(info.id)
+  if (!session?.process) throw new Error('Expected a spawned PTY process')
+  const kill = spyOn(session.process, 'kill')
+  await exited
+  expect(kill).toHaveBeenCalledTimes(1)
+  expect(session.status).toBe('exited')
+  expect(session.exitCode).toBe(3)
+  expect(onExit).toHaveBeenCalledTimes(1)
+})