openclaw/docs/gateway/background-process.md

summary, read_when, title

summary	read_when	title
Background exec execution and process management	Adding or modifying background exec behavior Debugging long-running exec tasks	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

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.
timeoutSeconds	Timeout in seconds (default tools.exec.timeoutSeconds); kills the process on expiry. Set timeoutSeconds: 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 retained output directly and disclose when earlier output exceeded the aggregate cap.
• 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.timeoutSeconds unless the call passes an explicit timeoutSeconds.
• Output stays in memory up to the per-session aggregate cap until the session is polled or cleared.
• Finished sessions expire after their configured TTL. The registry also retains at most 50 finished sessions and 2,000,000 total retained output characters, evicting the oldest records first. The newest completed session retains its capped per-session aggregate even when that record alone exceeds the global limit.
• 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 aggregate cap in characters. Default 200000, clamped 1000-200000.
OPENCLAW_BASH_PENDING_MAX_OUTPUT_CHARS	Pending stdout/stderr cap per stream. Default 30000, clamped 1000-200000 and limited by the aggregate cap.
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.timeoutSeconds	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.

Worker environments

On a paired-node or node-backed cloud worker, background processes belong to the session's environment. Finishing or cancelling a turn leaves already-backgrounded commands running. A later turn in the same environment can use process to poll, send input, or stop them; foreground commands still stop when their turn is cancelled.

The retained worker occupies one node worker slot. Reusing it needs no additional slot. If a command finishes between turns, its retained output remains available to the next turn, subject to the normal process output limits and TTL. Once a turn finishes with no live background commands, the worker exits. Moving or retiring the environment, replacing its ownership, or stopping the node also stops its processes. Process handles do not survive a worker or node restart.

If the node's pairing is revoked or its provider no longer recognizes the lease, the session placement fails. Physical cleanup can remain pending until OpenClaw confirms that the exact worker has stopped; an unconfirmed stop does not release its ownership record.

Worker completion does not currently wake the Gateway session automatically; use process poll in a later turn to inspect the result. Closing a portal closes its proxy, not the development server: stop the server with process kill.

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/close. 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.
• Resetting or deleting a session clears only its completed background processes; other sessions, explicit shared scopes, and running processes remain unaffected.
• 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).
• process poll and process log distinguish output discarded at the aggregate retention cap from output merely omitted by the pending buffer or retained tail. Discarded output cannot be recovered; paged logs can inspect only the retained portion.
• 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" }

Related

• Exec tool
• Exec approvals