Slack publishing as software
Codex runs postqueen commands, reads the JSON results and verifies each step, so your Slack pipeline behaves like any other task it automates in CI or cron.
SlackAutomate Slack with Codex
Point Codex at the postqueen CLI and it creates, schedules and verifies Slack messages as one repeatable task you can rerun any time.
Quick start
Set up the CLI inside the workspace Codex uses, then describe the Slack outcome you want in the task prompt.
Codex session
# Inside a Codex sessionnpm install -g postqueenexport POSTQUEEN_API_KEY=your_api_key # Then prompt:# "Create this week's Slack messages# from notes.md and schedule them# with postqueen"What Codex can run on Slack
Windows that fit Slack
Tell Codex when your channels are busiest and it schedules messages into that window on Slack, day after day, without reminders.
The right channels, every time
Codex lists your connected channels before it posts, so messages land exactly where they should and announcements stay consistent.
Drafts until you are ready
Ask Codex for drafts only. They sit on the postqueen calendar unscheduled, so you can edit them and pick the time yourself, and nothing reaches your workspace members on Slack until you do.
Three steps to a full queue
Discover Slack
Codex calls postqueen to list your connected channels and sees what Slack supports, so drafts start from real capabilities, not guesses.
Draft with Codex
Give it the brief. The agent writes Slack-shaped messages and proposes publish times that match when your workspace members are around.
Check and publish
Look over the queue on the postqueen calendar and change anything you want. postqueen publishes each post at its time, and Codex can pull the results after.
What Slack allows
Codex reads these limits from postqueen before it composes, so a draft that would be rejected never reaches the queue.
- Message length
- Up to 40,000 characters per message through the Slack API
- Formatting
- Slack mrkdwn: bold, italics, code blocks, quotes and links
- File uploads
- Files up to 1 GB each
- Rate limit
- About one message per second per channel, with short bursts allowed
- App requirement
- The postqueen app must be installed in the workspace and invited to private channels
SlackEverything postqueen does on Slack
Scheduling, AI drafts, analytics and team roles, in one guide.
F.A.Q.
Frequently asked questions
How does Codex connect Slack to postqueen?
Install the postqueen CLI where Codex runs commands and export your API key. Every command returns JSON, so the agent can create, schedule and list Slack messages reliably.
Can Codex schedule Slack messages at exact times?
Yes. Give it exact slots or a rule like mornings at nine and it sets publish times on the messages it creates, keeping your channels active on a steady rhythm.
Will Codex publish to Slack on its own?
Only if you ask it to. Tell it to save drafts and nothing is scheduled: the messages wait on the calendar until you set a time. Tell it to schedule, and they go out at the times you can see, which is the setup most people move to once they trust the output.
Can one brief cover Slack and other channels too?
Yes. postqueen connects 30 channels, so Codex can turn the same brief into Slack messages plus adapted versions for every other channel you run.
Does Codex access cost extra on postqueen?
No. The agent uses your regular API key and plan limits: unlimited posts on every plan, and channel counts from 5 on Creator up to uncapped on Ultimate.
Can AI draft my Slack announcements?
Yes. The built-in assistant writes and rewrites messages in a tone that fits your team, and nothing publishes until you schedule it. You can also drive Slack posting from Claude Code, ChatGPT or any other agent through the MCP server and the CLI.
When should I schedule Slack messages?
Match your audience's working hours: announcements land best when the channel is awake, which may span several timezones. Scheduling lets one person queue the message once instead of someone staying online to post it.
Ready to get started?
Queue this week's posts in minutes, or hand the whole thing to your favorite AI. postqueen keeps publishing either way.
Seven days free. Cancel in one click from settings.