---
summary: "Exec tool usage, stdin modes, and TTY support"
read_when:
  - Using or modifying the exec tool
  - Debugging stdin or TTY behavior
---

# Exec tool

Run shell commands in the workspace. Supports foreground + background execution via `process`.
If `process` is disallowed, `exec` runs synchronously and ignores `yieldMs`/`background`.
Background sessions are scoped per agent; `process` only sees sessions from the same agent.

## Parameters

- `command` (required)
- `workdir` (defaults to cwd)
- `env` (key/value overrides)
- `yieldMs` (default 10000): auto-background after delay
- `background` (bool): background immediately
- `timeout` (seconds, default 1800): kill on expiry
- `pty` (bool): run in a pseudo-terminal when available (TTY-only CLIs, coding agents, terminal UIs)
- `host` (`sandbox | gateway | node`): where to execute
- `security` (`deny | allowlist | full`): enforcement mode for `gateway`/`node`
- `ask` (`off | on-miss | always`): approval prompts for `gateway`/`node`
- `node` (string): node id/name for `host=node`
- `elevated` (bool): alias for `host=gateway` + `security=full` when sandboxed and allowed

Notes:
- `host` defaults to `sandbox`.
- `elevated` is ignored when sandboxing is off (exec already runs on the host).
- `gateway`/`node` approvals are controlled by `~/.clawdbot/exec-approvals.json`.
- `node` requires a paired node (companion app or headless node host).
- If multiple nodes are available, set `exec.node` or `tools.exec.node` to select one.
- On non-Windows hosts, exec uses `SHELL` when set; if `SHELL` is `fish`, it prefers `bash` (or `sh`)
  from `PATH` to avoid fish-incompatible scripts, then falls back to `SHELL` if neither exists.

## Config

- `tools.exec.notifyOnExit` (default: true): when true, backgrounded exec sessions enqueue a system event and request a heartbeat on exit.
- `tools.exec.host` (default: `sandbox`)
- `tools.exec.security` (default: `deny` for sandbox, `allowlist` for gateway + node when unset)
- `tools.exec.ask` (default: `on-miss`)
- `tools.exec.node` (default: unset)
- `tools.exec.pathPrepend`: list of directories to prepend to `PATH` for exec runs.
- `tools.exec.safeBins`: stdin-only safe binaries that can run without explicit allowlist entries.

Example:
```json5
{
  tools: {
    exec: {
      pathPrepend: ["~/bin", "/opt/oss/bin"]
    }
  }
}
```

### PATH handling

- `host=gateway`: merges your login-shell `PATH` into the exec environment (unless the exec call
  already sets `env.PATH`). The daemon itself still runs with a minimal `PATH`:
  - macOS: `/opt/homebrew/bin`, `/usr/local/bin`, `/usr/bin`, `/bin`
  - Linux: `/usr/local/bin`, `/usr/bin`, `/bin`
- `host=sandbox`: runs `sh -lc` (login shell) inside the container, so `/etc/profile` may reset `PATH`.
  Clawdbot prepends `env.PATH` after profile sourcing; `tools.exec.pathPrepend` applies here too.
- `host=node`: only env overrides you pass are sent to the node. `tools.exec.pathPrepend` only applies
  if the exec call already sets `env.PATH`. Node PATH overrides are accepted only when they prepend
  the node host PATH (no replacement).

Per-agent node binding (use the agent list index in config):

```bash
clawdbot config get agents.list
clawdbot config set agents.list[0].tools.exec.node "node-id-or-name"
```

Control UI: the Nodes tab includes a small “Exec node binding” panel for the same settings.

## Session overrides (`/exec`)

Use `/exec` to set **per-session** defaults for `host`, `security`, `ask`, and `node`.
Send `/exec` with no arguments to show the current values.

Example:
```
/exec host=gateway security=allowlist ask=on-miss node=mac-1
```

## Exec approvals (companion app / node host)

Sandboxed agents can require per-request approval before `exec` runs on the gateway or node host.
See [Exec approvals](/tools/exec-approvals) for the policy, allowlist, and UI flow.

## Allowlist + safe bins

Allowlist enforcement matches **resolved binary paths only** (no basename matches). When
`security=allowlist`, shell commands are auto-allowed only if every pipeline segment is
allowlisted or a safe bin. Chaining (`;`, `&&`, `||`) and redirections are rejected in
allowlist mode.

## Examples

Foreground:
```json
{"tool":"exec","command":"ls -la"}
```

Background + poll:
```json
{"tool":"exec","command":"npm run build","yieldMs":1000}
{"tool":"process","action":"poll","sessionId":"<id>"}
```

Send keys (tmux-style):
```json
{"tool":"process","action":"send-keys","sessionId":"<id>","keys":["Enter"]}
{"tool":"process","action":"send-keys","sessionId":"<id>","keys":["C-c"]}
{"tool":"process","action":"send-keys","sessionId":"<id>","keys":["Up","Up","Enter"]}
```

Submit (send CR only):
```json
{"tool":"process","action":"submit","sessionId":"<id>"}
```

Paste (bracketed by default):
```json
{"tool":"process","action":"paste","sessionId":"<id>","text":"line1\nline2\n"}
```

## apply_patch (experimental)

`apply_patch` is a subtool of `exec` for structured multi-file edits.
Enable it explicitly:

```json5
{
  tools: {
    exec: {
      applyPatch: { enabled: true, allowModels: ["gpt-5.2"] }
    }
  }
}
```

Notes:
- Only available for OpenAI/OpenAI Codex models.
- Tool policy still applies; `allow: ["exec"]` implicitly allows `apply_patch`.
- Config lives under `tools.exec.applyPatch`.
