Post to Slack from Codex

Codex can post to Slack channels through Postiz. Install the Postiz skill or add the Postiz MCP server to Codex, connect your Slack workspace in Postiz, then name the channel and the message. Codex drafts the update, attaches uploaded images or files, and schedules it, so team announcements go out without you switching windows.

Setup Guide GitHub

Please make sure there is always a human in the loop.

Last updated: September 2026

How do I post to Slack from Codex?

Set up Codex once with the Postiz skill or the Postiz MCP server, connect Slack in Postiz, then ask. The whole setup takes a few minutes.

Setup, then just ask

# One-time setup, option A: Postiz skill + CLI
npx skills add gitroomhq/postiz-agent
export POSTIZ_API_KEY=your_api_key   # or: postiz auth:login

# One-time setup, option B: Postiz MCP server (OAuth, no key)
codex mcp add postiz --url https://mcp.postiz.com/mcp-oauth-dynamic
codex mcp login postiz

# Then just ask Codex:
> Post the weekly update to #general
  on Slack tomorrow at 9am

Codex: Done! Your Slack post is scheduled.

Slack-Specific Features

📢

Channel Messaging

Post messages to any Slack channel your bot has access to. Share updates, announcements, and notifications automatically.

⏰

Scheduled Messages

Schedule messages for the perfect time. Queue up announcements, reminders, and updates to post when your team is most active.

🖼

Media Sharing

Attach images, files, and rich media to your Slack messages. Share screenshots, reports, and visual updates with your team.

👥

Team Communications

Automate recurring team updates, standup summaries, and status reports across multiple channels simultaneously.

🤖

Bot Integration

Leverage Slack bot tokens for seamless posting. Your AI agent authenticates once and posts on behalf of your workspace.

📅

Multi-Channel Posting

Target different channels for different content types. Send engineering updates to #dev and marketing wins to #general.

How does Codex post to Slack?

You describe what you want in plain language and Codex handles the Postiz calls for you. Here is how a typical conversation goes.

Find Your Slack Integration

Ask Codex whether your Slack account is connected. It also checks which options the platform supports.

Example conversation

> Is my Slack account connected to Postiz?

Codex: Yes — your Slack account is connected
  and ready. Want me to post something?

Choose Your Channel

Identify the Slack channel ID where you want to post. You can find channel IDs in Slack by right-clicking a channel and selecting 'View channel details'.

Example conversation

> Draft a Slack post about our new
  feature launch

Codex: Here's a draft for Slack:
  "We just shipped something big..."
  Want me to add media and schedule it?

Create Your Post

Send a message to your Slack channel with the channel ID in settings. Schedule it for later or post immediately.

Example conversation

> Yes — add screenshot.png and schedule
  it for tomorrow at 9am

Codex: Done! Scheduled on Slack for
  tomorrow at 9:00 AM.

Slack Settings Reference

Mention any of these in plain language and Codex sets them for you. These are the Slack options it can apply to any post.

Field	Type	Required	Description
`__type`	string	Yes	Must be "slack"
`channel`	string	Yes	Slack channel ID (e.g. C12345)

Common Configurations

Ask Codex for any of these common Slack scenarios and it applies the matching settings.

General Channel Announcement

Just ask

> Post it with: General Channel Announcement

Codex: Got it. Applying:
  channel: C12345

Engineering Updates

Just ask

> Post it with: Engineering Updates

Codex: Got it. Applying:
  channel: C67890

Marketing Channel Post

Just ask

> Post it with: Marketing Channel Post

Codex: Got it. Applying:
  channel: CABCDE

What is Codex?

Codex is OpenAI's coding agent. It runs as the Codex CLI in your terminal (npm install -g @openai/codex), as an IDE extension, and in the cloud, and it can run shell commands and call MCP servers, which is how it drives Postiz. Codex is not ChatGPT: ChatGPT is the chat assistant on chatgpt.com and connects to Postiz differently (see the ChatGPT guide). For the full setup, start at the Codex + Postiz hub.

💻

Terminal & IDE Native

Codex runs in your terminal or IDE. You type what you want in plain English and it handles Postiz for you — no extra configuration needed.

🔧

Autonomous Execution

Codex runs commands inside a sandbox with approval rules you control, and works through multi-step tasks like discovering channels, uploading media, and scheduling Slack posts.

⚡

Parallel Tasks

Run multiple Codex tasks simultaneously. Schedule posts to different platforms in parallel while Codex handles other coding work.

How Postiz Works with Codex

Codex discovers Postiz two ways: the postiz skill, which it loads from .agents/skills or ~/.agents/skills and which you can invoke with $postiz, or the Postiz MCP server added with codex mcp add. Either way it learns the available tools and chains them for Slack workflows.

✓Install the Postiz skill with npx skills add, or add the Postiz MCP server with codex mcp add
✓Codex loads skills from .agents/skills and reads SKILL.md to learn the Postiz CLI
✓Authenticate with POSTIZ_API_KEY or postiz auth:login; the MCP route uses OAuth instead
✓Codex runs commands in its sandbox and asks for approval based on your permission settings
✓Works alongside your coding tasks in parallel

Install Postiz

# Install the Postiz skill
npx skills add gitroomhq/postiz-agent

# Set your API key
export POSTIZ_API_KEY=your_api_key

# Or add the Postiz MCP server instead (OAuth, no API key)
codex mcp add postiz --url https://mcp.postiz.com/mcp-oauth-dynamic
codex mcp login postiz

# Then ask, interactively or headless
codex "list my social media integrations"
codex exec "post today's changelog to Slack"

Slack Posting with Codex

Tell Codex what to post from your terminal or IDE — it discovers your integrations via Postiz and handles the entire publishing workflow.

💻

Just Ask Codex

Terminal and IDE integration

Tell Codex what to post from your terminal or IDE — it discovers your integrations via Postiz and handles the entire publishing workflow.

Codex CLI

$ codex "Post to Slack about our
  new feature launch, schedule for
  tomorrow at 9am"

Codex: I'll handle that.
  Found your Slack integration.
  Composing and scheduling the post.

  Done! Your post is scheduled.
  Post ID: abc-123

💻

Parallel Tasks

Multiple tasks at once

Codex can handle multiple tasks in parallel. Schedule posts to different platforms while it works on other coding tasks simultaneously.

Codex Parallel Tasks

# Run multiple posting tasks in parallel
$ codex "Schedule a post about our
  launch to X for tomorrow 9am" &

$ codex "Write a LinkedIn article
  about our new feature and schedule
  for tomorrow noon" &

$ codex "Fix the bug in auth.ts"

# All three tasks run simultaneously

Why Codex + Postiz for Slack

Codex's autonomous execution makes Postiz a natural fit. The agent reads the SKILL.md to understand every available command, then autonomously chains them together for Slack workflows.

✓Runs in your terminal or IDE — just type what you want
✓Autonomous execution in sandboxed environments
✓Parallel task support — post while coding
✓Channel targeting applied automatically based on your instructions
✓Cross-post to Slack + other platforms in a single session
✓Powered by OpenAI's most capable models

SKILL.md (loaded by Codex from .agents/skills)

---
name: postiz
description: Social media automation
  CLI for scheduling posts across
  30+ platforms including Slack
homepage: https://docs.postiz.com/public-api/introduction
---

# Loaded by Codex from .agents/skills
# Invoke explicitly with $postiz

# Available Commands
- postiz integrations:list
- postiz integrations:settings <id>
- postiz posts:create
- postiz upload <file>
- postiz analytics:platform <id>

# Slack Settings
channel (required)

Also Works with Claude Code

Postiz works with any AI agent that can run commands or call MCP tools — you ask, the agent does the work. That includes Anthropic's Claude Code: see the Claude Code Slack guide, or the Postiz Agent page for any other agent.

Claude Code

by Anthropic

Claude reads the Postiz skill so it knows what it can do, then autonomously discovers your Slack integration, identifies the correct channel, and sends your message.

Claude Code

> Post a deployment update to #engineering
  on Slack

Claude: Done! Scheduled on Slack for
  tomorrow at 9:00 AM.

Can Codex post to Slack and other platforms at once?

Post the same announcement to Slack and other platforms in a single request. Each platform gets its own settings.

Example

> Post "Excited to announce our new feature!" to
  Slack and LinkedIn tomorrow at 9am, then schedule
  a daily tip on Slack every weekday at 10am

Codex: Done! Scheduled:
  - Slack + LinkedIn: tomorrow 9:00 AM
  - Daily tips on Slack: Mon-Fri 10:00 AM

What can I ask Codex to post on Slack?

Codex takes plain-English prompts in an interactive session, as a one-off codex exec command, or through the $postiz skill. These are the kinds of prompts people type for Slack.

Prompts for Slack

> Post the weekly engineering update to #general on Slack
  tomorrow 9am, summarize this week's merged PRs

$ codex exec "Send 'Staging deploy done' with ./reports/coverage.png
  to the #qa Slack channel"

> $postiz Cancel tomorrow's Slack post in #marketing and
  reschedule it for Thursday

What Slack rules should Codex follow?

These are the Slack limits and required settings Postiz enforces. Codex reads them from postiz integrations:settings, and you can mention any of them in your prompt.

✓channel is required and holds the Slack channel ID (like C12345); Codex resolves #channel-name for you.
✓The Postiz Slack app must be a member of private channels before it can post there.
✓Images and files go through postiz upload before they are attached.
✓Recurring updates are scheduled as one post per occurrence, or generated by a codex exec cron job.

Codex and Slack FAQ

How do I post to Slack from Codex?

Install the Postiz skill with npx skills add gitroomhq/postiz-agent, or add the Postiz MCP server with codex mcp add postiz --url https://mcp.postiz.com/mcp-oauth-dynamic. Connect Slack in Postiz once, then ask Codex in plain English what to post and when. Codex resolves the Slack settings, uploads any media, and schedules the post.

Which Slack channels can Codex post to?

Any channel the Postiz Slack app is a member of. Public channels are listed automatically through postiz integrations:settings; for private channels, invite the Postiz app first. Codex maps the channel name you mention to its ID, which is the required channel setting, and asks if it finds no match.

Can Codex schedule recurring Slack updates?

Yes, by creating one scheduled post per occurrence. Ask for "a Monday 9am update for the next four weeks" and Codex schedules four posts through Postiz. For truly automated recurring content, run codex exec from a cron job that generates the message from your repo and schedules it.

Can Codex post to Slack on a schedule without me watching?

Yes. Postiz stores scheduled Slack posts and publishes them at the chosen time, so Codex does not need to stay open. For unattended runs, call codex exec with your prompt from a script or cron job. Keep a human reviewing the output, since Codex will publish exactly what it is told to publish.

Do I need a Postiz API key to post to Slack from Codex?

Not with the MCP route. Run codex mcp login postiz and Codex signs in to your Postiz account over OAuth, so it only reaches channels you already connected, including Slack. The CLI skill route needs either postiz auth:login or a POSTIZ_API_KEY environment variable. Your Slack login itself never leaves Postiz.

Is posting to Slack from Codex the same as posting from ChatGPT?

No. Codex is OpenAI's coding agent for your terminal and IDE, and it reaches Postiz through the Postiz skill or MCP server. ChatGPT is the chat assistant on chatgpt.com, which connects to Postiz as an app or custom MCP connector. Both can publish to Slack; see the ChatGPT guide for that setup.