Headless / non-TTY mode

When stdin or stdout isn't a TTY (piped input, CI jobs, scripts), factory skips the interactive TUI and runs in headless mode: it reads stdin to EOF as a single user prompt, executes one agent turn, streams the assistant's text to stdout, and writes tool diagnostics to stderr.

echo "what does src/index.ts do?" | factory -p anthropic -m claude-sonnet-4-6

The detection is automatic — explicit overrides are not needed.

Permissions in headless mode

There's no TTY to answer permission prompts, so any tool that isn't pre-allowed will be denied and the process exits with code 3. To grant access, list the tools in your config:

{
  "permissions": {
    "allowAll": ["Read", "Glob", "Grep"]
  }
}

Be deliberate about which tools you allow — Bash, Edit, and Write execute side effects without confirmation in this mode. The same goes for any MCP tools you've registered: their names go in the same allowAll array.

Exit codes

Code	Meaning
0	Success
1	Agent error (provider failure, unhandled rejection, etc.)
2	Empty stdin (nothing for the agent to act on)
3	Permission denied (no TTY to prompt)
4	Turn limit hit (--turn-timeout)
5	Token limit / context-window exhausted
130	SIGINT

Session logs

Session logs are written exactly as in interactive mode, so headless runs are still inspectable in ~/.factory/sessions/. Combined with --strict-log, you get a CI-friendly contract: if logging fails, the run fails non-zero.

Patterns

One-shot question against the codebase:

echo "summarize what src/core/agent/run-agent.ts does" | factory \
  -p anthropic -m claude-sonnet-4-6 --no-clear

Read-only research with all read tools allowlisted:

{
  "permissions": {
    "allowAll": ["Read", "Glob", "Grep", "WebFetch"]
  }
}

Hardened CI run that captures the session log and fails on log errors:

factory --strict-log < prompt.txt 2> stderr.log
echo "exit=$?"
ls -la ~/.factory/sessions/  # latest session log captures every event

Combine with --turn-timeout to bound run time in CI:

factory --turn-timeout 120 < prompt.txt