Background exec and process tool — openclaw

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

exec tool

Parameters:

Parameter	Description
`command`	Required. Shell command to run.
`workdir`	Working directory; omit to use the default cwd.
`env`	Extra environment variables for the command.
`yieldMs`	Milliseconds to wait before backgrounding (default 10000).
`background`	Run in background immediately.
`timeout`	Timeout in seconds (default `tools.exec.timeoutSec`); kills the process on expiry. Set `timeout: 0` to disable the exec process timeout for that call.
`pty`	Run in a pseudo-terminal when available (TTY-required CLIs, coding agents).
`elevated`	Run outside the sandbox if elevated mode is enabled/allowed (`gateway` by default, or `node` when the exec target is `node`).
`host`	Exec target: `auto`, `sandbox`, `gateway`, or `node`.
`node`	Node id/name, used with `host: "node"`.

Behavior:

Foreground runs return output directly.
When backgrounded (explicit or via yieldMs timeout), the tool returns status: "running" + sessionId and a short output tail.
Backgrounded and yieldMs runs inherit tools.exec.timeoutSec unless the call passes an explicit timeout.
Output stays 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.
For long-running work that starts now: start it once and rely on automatic completion wake (when enabled) once the command emits output or fails.
If automatic completion wake is unavailable, or you need quiet-success confirmation for a command that exits cleanly with no output, poll with process.
Don't emulate reminders or delayed follow-ups with sleep loops or repeated polling — use cron for future work.

Env overrides

Variable	Effect
`OPENCLAW_BASH_YIELD_MS`	Default yield before backgrounding (ms). Default 10000, clamped 10-120000.
`OPENCLAW_BASH_MAX_OUTPUT_CHARS`	In-memory output cap (chars).
`OPENCLAW_BASH_PENDING_MAX_OUTPUT_CHARS`	Pending stdout/stderr cap per stream (chars).
`OPENCLAW_BASH_JOB_TTL_MS`	TTL for finished sessions (ms), bounded to 1m-3h.
`OPENCLAW_PROCESS_INPUT_WAIT_IDLE_MS`	Idle-output threshold before writable background sessions are marked as likely waiting for input. Default 15000.

Config (preferred over env overrides)

Key	Default	Effect
`tools.exec.backgroundMs`	10000	Same as `OPENCLAW_BASH_YIELD_MS`.
`tools.exec.timeoutSec`	1800	Default per-call timeout.
`tools.exec.cleanupMs`	1800000	Same as `OPENCLAW_BASH_JOB_TTL_MS`.
`tools.exec.notifyOnExit`	true	Enqueue a system event + request heartbeat when a backgrounded exec exits.
`tools.exec.notifyOnExitEmptySuccess`	false	Also enqueue completion events for successful backgrounded runs with no output.

Child process bridging

When spawning long-running child processes outside the exec/process tools (CLI respawns, gateway helpers), attach the child-process bridge helper so termination signals forward and listeners detach on exit/error. This avoids orphaned processes on systemd and keeps shutdown consistent across platforms.

process tool

Actions:

Action	Effect
`list`	Running + finished sessions.
`poll`	Drain new output for a session (also reports exit status).
`log`	Read aggregated output and input-recovery hints. Supports `offset` + `limit`.
`write`	Send stdin (`data`, optional `eof`).
`send-keys`	Send explicit key tokens or bytes to a PTY-backed session.
`submit`	Send Enter/carriage return to a PTY-backed session.
`paste`	Send literal text, optionally wrapped in bracketed paste mode.
`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 only, not on disk. Sessions are lost on process restart.
A live background session blocks cooperative host suspension and safe Gateway restart until the process owner confirms its actual exit.
process remove can hide a running session immediately after requesting termination; suspension and restart remain blocked until exit confirmation.
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.
Use poll/log for status, logs, or completion confirmation when automatic completion wake is unavailable.
Use log before recovering an interactive CLI, so the current transcript, stdin state, and input-wait hint are visible together.
Use write/send-keys/submit/paste/kill when you need input or intervention.
process list includes a derived name (command verb + target) for quick scans.
process list, poll, and log report waitingForInput only when the session still has writable stdin and has been idle longer than the input-wait threshold (default 15000 ms, OPENCLAW_PROCESS_INPUT_WAIT_IDLE_MS).
process log uses line-based offset/limit. When both are omitted, it returns the last 200 lines with a paging hint. When offset is set and limit isn't, it returns from offset to the end (not capped to 200).
poll's timeout waits up to that many milliseconds before returning; values above 30000 are clamped to 30000.
Polling is for on-demand status, not wait-loop scheduling. If the work should happen later, use cron.

Examples

Run a long task and poll later:

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

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

Inspect an interactive session before sending input:

{ "tool": "process", "action": "log", "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" }

Send PTY keys:

{ "tool": "process", "action": "send-keys", "sessionId": "<id>", "keys": ["C-c"] }

Submit current line:

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

Paste literal text:

{ "tool": "process", "action": "paste", "sessionId": "<id>", "text": "line1\nline2\n" }

Source: docs/gateway/background-process.md