* fix(sandbox): stop blocking bash commands from hanging the turn
Starting a server through the host bash tool (e.g. `python -m http.server`)
could hang the whole turn for the full 600s timeout. `LocalSandbox.execute_command`
used `subprocess.run(capture_output=True)`, whose captured pipes are inherited
by any process the command spawns — so a backgrounded long-lived process
(`server &`) keeps the read end open and blocks `communicate()` until the
timeout fires, even though the foreground command already returned. Commands
that read stdin blocked the same way, and on timeout only the direct child was
killed, leaving orphaned process groups.
Rework the POSIX path to capture stdout/stderr via temp files instead of pipes,
take stdin from /dev/null, and run the command in its own session/process group:
- Backgrounded long-lived processes (servers) now return immediately while the
process keeps running.
- A command reading stdin gets immediate EOF instead of blocking.
- A genuinely blocking foreground command is bounded by a configurable
wall-clock timeout; on timeout the whole process group is killed and the agent
gets an explanatory notice telling it to background long-lived processes.
The timeout is configurable via `sandbox.bash_command_timeout` (default 600).
The Windows path is unchanged. Adds focused regression tests and updates docs.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* fix(sandbox): instruct the agent to background long-lived processes
The code fix bounds a foreground server with a timeout, but the turn still
waits the full timeout before the run continues. Add the prompt-side half:
the bash tool description now tells the model to ALWAYS start long-lived
processes (e.g. web servers) in the background with output redirected, so the
tool returns immediately. The timeout notice points at the same readable
workspace log path. Pins the guidance with a test.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* fix(sandbox): make fallback-kill exception explicit and observable
Address automated review: the inner `except OSError: pass` in
_terminate_process_group silently swallowed the case where the direct-child
fallback kill found the process already gone. Make the intent explicit with a
comment and a debug log instead of a bare pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* fix(sandbox): address bash timeout review feedback
* fix(sandbox): document fd cleanup races
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
