Get a desktop or Slack notification when Codex finishes a turn: notify and tui.notifications

Hand Codex a longer task, switch to something else, and you can easily miss the moment it finishes. Codex CLI offers two mechanisms: notify, which launches an external program when a turn completes, and tui.notifications, which controls the terminal's own notifications.

In short: write an argv array such as notify = ["python3", "/path/to/notify.py"], and Codex runs that program with a single JSON argument at the end of every turn. From there you can post a desktop notification, hit a Slack webhook, or anything else.

notify: launching an external program

In ~/.codex/config.toml, list the command as an array. Unset means disabled.

notify = ["python3", "/Users/you/.codex/notify.py"]

The program receives one JSON string as its argument and should exit 0 on success. The main fields:

Field	Contents
type	event type; currently agent-turn-complete
thread-id	the session (thread) identifier
turn-id	the turn identifier
cwd	the working directory
input-messages	the user messages for that turn
last-assistant-message	the assistant's final output text

macOS example

Using terminal-notifier (installable with Homebrew):

#!/usr/bin/env python3
import json, subprocess, sys

payload = json.loads(sys.argv[1])
if payload.get("type") != "agent-turn-complete":
    sys.exit(0)
title = "Codex: turn complete"
body = (payload.get("last-assistant-message") or "")[:120]
subprocess.run(["terminal-notifier", "-title", title, "-message", body, "-group", payload.get("thread-id", "")])

Linux example

With notify-send you can skip the script entirely; the sample configuration shows this form.

notify = ["notify-send", "Codex"]

The JSON string then becomes the notification body as is. Insert a script like the one above if you want it tidier.

Sending to Slack

For a Slack Incoming Webhook, have the script trim last-assistant-message and POST it. Read the webhook URL from an environment variable rather than writing it into config.toml.

tui.notifications: controlling terminal notifications

The terminal's own notifications are configured under [tui].

[tui]
# true / false, or a list of types
notifications = ["agent-turn-complete", "approval-requested"]
# unfocused (default) | always
notification_condition = "unfocused"
# auto (default) | osc9 | bel
notification_method = "auto"

Key	Values	Meaning
notifications	true / false / list	on by default; restrict to agent-turn-complete and approval-requested
notification_condition	unfocused / always	default fires only when the terminal is not focused
notification_method	auto / osc9 / bel	auto prefers OSC 9 when the terminal supports it, else BEL (\x07)

notify and tui.notifications are independent. For external notifications only, set notifications = false; to still hear about pending approvals, keep approval-requested in the list.

The overall structure of the config file is covered in the hub article Configuring Codex with config.toml, and when approvals are requested in Codex approval modes and sandbox settings.

Summary

• notify is an argv array, run with one JSON argument on every agent-turn-complete
• The JSON carries type, thread-id, turn-id, cwd, input-messages, and last-assistant-message
• terminal-notifier on macOS or a bare notify-send on Linux is enough to start
• Truncate the body before sending it to external services and keep webhook URLs in environment variables
• Terminal notifications are separate: [tui] notifications, notification_condition, notification_method