* fix(sandbox): serialize concurrent exec_command calls in AioSandbox
The AIO sandbox container maintains a single persistent shell session
that corrupts when multiple exec_command requests arrive concurrently
(e.g. when ToolNode issues parallel tool_calls). The corrupted session
returns 'ErrorObservation' strings as output, cascading into subsequent
commands.
Add a threading.Lock to AioSandbox to serialize shell commands. As a
secondary defense, detect ErrorObservation in output and retry with a
fresh session ID.
Fixes#1433
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* fix(sandbox): address Copilot review findings
- Fix shell injection in list_dir: use shlex.quote(path) to escape
user-provided paths in the find command
- Narrow ErrorObservation retry condition from broad substring match
to the specific corruption signature to prevent false retries
- Improve test_lock_prevents_concurrent_execution: use threading.Barrier
to ensure all workers contend for the lock simultaneously
- Improve test_list_dir_uses_lock: assert lock.locked() is True during
exec_command to verify lock acquisition
* style: auto-format with ruff
---------
Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
a3bfea631c