From 78c25f30c57d18b954ad8a3bcd0df8faf8abdf28 Mon Sep 17 00:00:00 2001
From: Gaurav Ghosh <gaghosh@google.com>
Date: Wed, 8 Apr 2026 11:51:54 -0700
Subject: [PATCH] fix(core): prevent race condition crash during shell
 auto-promotion

---
 packages/core/src/services/shellExecutionService.ts | 5 +++++
 packages/core/src/tools/shell.ts                    | 8 +++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/packages/core/src/services/shellExecutionService.ts b/packages/core/src/services/shellExecutionService.ts
index 95b3f2d17b..ffc714b375 100644
--- a/packages/core/src/services/shellExecutionService.ts
+++ b/packages/core/src/services/shellExecutionService.ts
@@ -1341,6 +1341,11 @@ export class ShellExecutionService {
     const activePty = this.activePtys.get(pid);
     const activeChild = this.activeChildProcesses.get(pid);
 
+    // If the process has already exited, there is no need to background it.
+    if (!activePty && !activeChild) {
+      return;
+    }
+
     const resolvedSessionId =
       sessionId ?? activePty?.sessionId ?? activeChild?.sessionId;
     const resolvedCommand =
diff --git a/packages/core/src/tools/shell.ts b/packages/core/src/tools/shell.ts
index 0407cb99bf..053cc4b00d 100644
--- a/packages/core/src/tools/shell.ts
+++ b/packages/core/src/tools/shell.ts
@@ -515,7 +515,13 @@ export class ShellToolInvocation extends BaseToolInvocation<
         if (shouldAutoPromote && currentPid) {
           if (this._autoPromoteTimer) clearTimeout(this._autoPromoteTimer);
           this._autoPromoteTimer = setTimeout(() => {
-            ShellExecutionService.background(currentPid!);
+            const sessionId =
+              this.context.config?.getSessionId?.() ?? 'default';
+            ShellExecutionService.background(
+              currentPid!,
+              sessionId,
+              strippedCommand,
+            );
           }, waitMs);
         }
       };