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Blog Post 17 — Codex Headless Dispatch: codex exec Unlocks the Third Agent

Broader Goal (End of Previous PR)

PR #50 seeded the capability ledger with 20 PRs of Claude history and proved the AGY dispatch pipeline end-to-end. Codex was confirmed TTY-blocked — synlynk dispatch codex started the process but Codex exited immediately with stdin is not a terminal. The ledger had Claude and AGY data; Codex was a placeholder.

What Changed

The fix turned out to be a single baseline update. Codex ships a codex exec subcommand designed explicitly for non-interactive use. It reads the prompt from stdin (via - argument), runs without a TTY, and exits when done. The only other flags needed:

  • -s read-only — sandboxes any shell commands Codex issues during the task
  • --dangerously-bypass-approvals-and-sandbox — skips interactive approval prompts so the process runs unattended

Updated baseline in AGENT_CAPABILITY_BASELINES["codex"]:

"non_interactive_flags": [
    "exec", "-",
    "-s", "read-only",
    "--dangerously-bypass-approvals-and-sandbox",
],

This generates a dispatch shell command of:

codex exec - -s read-only --dangerously-bypass-approvals-and-sandbox < prompt.txt > log.txt 2>&1

No PTY wrapper, no tmux, no pexpect. One config change.

Verification

Dispatched a real task headlessly to confirm:

synlynk dispatch codex --task "List the top 3 functions in bin/synlynk.py by line count" --force-agent

Codex wrote Python AST code to parse bin/synlynk.py, counted lines per function, and returned:

1. main — 237 lines
2. _build_templates — 220 lines
3. init — 174 lines

Exit 0, 17,850 tokens used, 468 lines of log output including the tool call trace.

Test

test_codex_baseline_uses_exec_subcommand asserts that the shell command built by dispatch_agent("codex", ...) contains codex exec and --dangerously-bypass-approvals-and-sandbox. Test count: 318.

New Goalpost

All three agents — Claude, AGY, Codex — can now be dispatched headlessly via synlynk dispatch. The capability ledger has real data for Claude and AGY; Codex now needs live dispatch stories attested to complete its baseline. Definition B (three-agent Autopilot: PM Agent, Marketing Intern, Support Engineer) can begin.

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