Configuration and operations

Background Exec and Process Tool

OpenClaw runs shell commands through the exec tool and keeps long‑running tasks in memory. The process tool manages those background sessions.

exec tool

Key parameters:

  • command (required)
  • yieldMs (default 10000): auto‑background after this delay
  • background (bool): background immediately
  • timeout (seconds, default 1800): kill the process after this timeout
  • elevated (bool): run on host if elevated mode is enabled/allowed
  • Need a real TTY? Set pty: true.
  • workdir, env

Behavior:

  • Foreground runs return output directly.
  • When backgrounded (explicit or timeout), the tool returns status: "running" + sessionId and a short tail.
  • Output is kept in memory until the session is polled or cleared.
  • If the process tool is disallowed, exec runs synchronously and ignores yieldMs/background.
  • Spawned exec commands receive OPENCLAW_SHELL=exec for context-aware shell/profile rules.

Child process bridging

When spawning long-running child processes outside the exec/process tools (for example, CLI respawns or gateway helpers), attach the child-process bridge helper so termination signals are forwarded and listeners are detached on exit/error. This avoids orphaned processes on systemd and keeps shutdown behavior consistent across platforms. Environment overrides:

  • PI_BASH_YIELD_MS: default yield (ms)
  • PI_BASH_MAX_OUTPUT_CHARS: in‑memory output cap (chars)
  • OPENCLAW_BASH_PENDING_MAX_OUTPUT_CHARS: pending stdout/stderr cap per stream (chars)
  • PI_BASH_JOB_TTL_MS: TTL for finished sessions (ms, bounded to 1m–3h)

Config (preferred):

  • tools.exec.backgroundMs (default 10000)
  • tools.exec.timeoutSec (default 1800)
  • tools.exec.cleanupMs (default 1800000)
  • tools.exec.notifyOnExit (default true): enqueue a system event + request heartbeat when a backgrounded exec exits.
  • tools.exec.notifyOnExitEmptySuccess (default false): when true, also enqueue completion events for successful backgrounded runs that produced no output.

process tool

Actions:

  • list: running + finished sessions
  • poll: drain new output for a session (also reports exit status)
  • log: read the aggregated output (supports offset + limit)
  • write: send stdin (data, optional eof)
  • kill: terminate a background session
  • clear: remove a finished session from memory
  • remove: kill if running, otherwise clear if finished

Notes:

  • Only backgrounded sessions are listed/persisted in memory.
  • Sessions are lost on process restart (no disk persistence).
  • Session logs are only saved to chat history if you run process poll/log and the tool result is recorded.
  • process is scoped per agent; it only sees sessions started by that agent.
  • process list includes a derived name (command verb + target) for quick scans.
  • process log uses line-based offset/limit.
  • When both offset and limit are omitted, it returns the last 200 lines and includes a paging hint.
  • When offset is provided and limit is omitted, it returns from offset to the end (not capped to 200).

Examples

Run a long task and poll later:

{ "tool": "exec", "command": "sleep 5 && echo done", "yieldMs": 1000 }

{ "tool": "process", "action": "poll", "sessionId": "<id>" }

Start immediately in background:

{ "tool": "exec", "command": "npm run build", "background": true }

Send stdin:

{ "tool": "process", "action": "write", "sessionId": "<id>", "data": "y\n" }

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