Post to Slack from Hermes Agent

Hermes Agent can post and schedule Slack channel messages through Postiz. After you add the Postiz skill, you tell Hermes what to share and where from Telegram, Discord, WhatsApp, or the CLI. It resolves the Slack channel ID, attaches any uploaded media, and schedules the message through the Postiz Slack app.

Setup Guide GitHub

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

Last updated: September 2026

Post to Slack in Seconds

Setup, then just ask

# One-time setup
npx skills add gitroomhq/postiz-agent
export POSTIZ_API_KEY=your_api_key

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

Hermes Agent: 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 to post to Slack from Hermes Agent

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

Find Your Slack Integration

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

Example conversation

> Is my Slack account connected to Postiz?

Hermes Agent: 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

Hermes Agent: 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

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

Slack Settings Reference

Mention any of these in plain language and Hermes Agent 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 Hermes Agent for any of these common Slack scenarios and it applies the matching settings.

General Channel Announcement

Just ask

> Post it with: General Channel Announcement

Hermes Agent: Got it. Applying:
  channel: C12345

Engineering Updates

Just ask

> Post it with: Engineering Updates

Hermes Agent: Got it. Applying:
  channel: C67890

Marketing Channel Post

Just ask

> Post it with: Marketing Channel Post

Hermes Agent: Got it. Applying:
  channel: CABCDE

What is Hermes Agent?

Hermes Agent is an open-source AI agent from Nous Research, released under the MIT license. It runs on your own machine or server, you talk to it from Telegram, Discord, Slack, WhatsApp, Signal, or the CLI, and it executes tools such as the Postiz skill to post to Slack and other channels. It works with Nous Portal, OpenRouter, OpenAI, or your own model endpoint.

💬

Message From Anywhere

Talk to Hermes from Telegram, Discord, Slack, WhatsApp, Signal, email, or the terminal. Ask for a Slack post from whichever app you already have open.

⏰

Built-in Cron Scheduler

Create recurring jobs in plain language, such as weekdays at 9am. Hermes drafts and schedules Slack content through Postiz and reports back to your chat.

🔧

Open Source, Any Model

Hermes Agent is MIT licensed and self-hosted. Run it on Nous Portal, OpenRouter, OpenAI, or your own endpoint, and extend it with MCP servers or skills like Postiz.

How Postiz Works with Hermes Agent

Postiz ships as an agent skill in the agentskills.io SKILL.md format that Hermes Agent reads. The skill documents every Postiz CLI command, the credentials it needs, and the Slack settings, so Hermes knows how to list your channels, upload media, and create posts without any custom code.

✓Install the Postiz CLI (npm install -g postiz) and add the skill with npx skills add gitroomhq/postiz-agent
✓Hermes loads skills from ~/.hermes/skills and shows them with hermes skills list
✓Authenticate with POSTIZ_API_KEY, or run postiz auth:login for an OAuth device flow
✓Every Postiz command returns JSON, so Hermes can chain discovery, upload, and posting
✓Prefer MCP? Add https://mcp.postiz.com/mcp-oauth-dynamic under mcp_servers in ~/.hermes/config.yaml

Install Postiz

# Install the Postiz CLI and skill
npm install -g postiz
npx skills add gitroomhq/postiz-agent

# Authenticate: API key or OAuth device flow
export POSTIZ_API_KEY=your_api_key
# or: postiz auth:login

# Confirm Hermes can see the skill
hermes skills list

Slack Posting with Hermes Agent

Hermes Agent reads Postiz commands through its tool system, discovers your integrations, and handles the entire posting workflow — from content creation to scheduling.

🧠

From Any Chat App

Telegram, Discord, Slack, WhatsApp, Signal

Send a message to Hermes Agent from your favorite chat app. Its gateway runs in the background, so it picks up your message, discovers your Slack workspace via Postiz, and sends the message to the right channel — all while you go about your day.

Hermes Agent

You: Post to Slack about our new
  feature launch, schedule for tomorrow
  at 9am

Hermes: I'll handle that! Let me:
  1. Find your Slack integration
  2. Compose your post content
  3. Schedule for tomorrow 9:00 AM

  Done! Post scheduled successfully.
  Post ID: abc-123

🧠

Scheduled & Proactive

Built-in Hermes cron jobs

Hermes Agent has a built-in cron scheduler. Create a recurring job in plain language and Hermes drafts and schedules your Slack content through Postiz on that schedule, then reports back to whichever chat you use.

Hermes cron job

# From the terminal
hermes cron create "weekdays at 9am" \
  "Check ~/content/slack for new posts.
   Upload any media with postiz upload,
   then schedule each one to Slack
   for noon today via Postiz. Move posted
   files to ~/content/published."

# Or from any chat with Hermes
/cron add "weekdays at 9am" "Schedule
  today's Slack post via Postiz"

Why Hermes Agent + Postiz for Slack

Hermes Agent makes Postiz a natural fit for your Slack workflow. The agent discovers all available commands and autonomously chains them together.

✓Hermes Agent is MIT licensed and Postiz has a public API, so nothing is locked in
✓Chat-first: ask for a Slack post from Telegram, Discord, Slack, WhatsApp, or Signal
✓Cron jobs in plain language for hands-free recurring Slack posts
✓Cross-post to Slack and other channels in one request, each with its own settings
✓Model-agnostic: run Hermes on Nous Portal, OpenRouter, OpenAI, or your own endpoint
✓Credentials stay in Postiz; Hermes only holds a Postiz API key or OAuth session

SKILL.md (what Hermes reads)

---
name: postiz
description: Postiz is a tool to schedule
  social media and chat posts to 28+
  channels including Slack
homepage: https://docs.postiz.com/public-api/introduction
---

# Commands Hermes can run
postiz auth:status
postiz integrations:list
postiz integrations:settings <id>
postiz upload <file>
postiz posts:create -i <id> -c "..." -s <iso>
postiz posts:list
postiz analytics:platform <id>

# Slack settings
channel

Using a different agent for Slack?

Postiz works with any AI agent that can run CLI commands or call MCP tools, and the Slack settings on this page are the same for every agent. Read the same guide for Claude Code, OpenClaw, Codex. Or see the guide for any AI agent and the Postiz MCP server.

Slack + Other Platforms

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

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

What can you ask Hermes Agent to do on Slack?

You can ask Hermes Agent to create, schedule, cancel, and measure Slack posts in plain language. These are the kinds of requests it handles through Postiz.

Ask Hermes Agent

> Post the weekly update to #general on Slack tomorrow at 9am.

Hermes resolves the channel ID for #general and schedules the message via Postiz.

Ask Hermes Agent

> Send the deploy summary with graph.png to #engineering on Slack right now.

Hermes uploads the image and posts the message with the attachment immediately.

Ask Hermes Agent

> Every Monday at 8am, post a reminder about standup and the sprint goals to #team on Slack.

Hermes creates a cron job that drafts the reminder and schedules it through Postiz.

Slack rules Hermes Agent has to follow

Postiz validates every Slack post before it is scheduled, so these limits and required settings decide whether a request succeeds.

▸The Postiz Slack app must be added to your workspace and invited to the channel before Postiz can post there.
▸channel is a Slack channel ID such as C12345, not a #name. Hermes resolves it from the channels Postiz can see.
▸Messages post as the Postiz app, not as your user account.
▸Files must be uploaded with postiz upload before they can be attached.

Hermes Agent and Slack: frequently asked questions

Can Hermes Agent post to Slack?

Yes. With the Postiz skill installed, Hermes Agent sends and schedules messages to any Slack channel the Postiz app has joined. It can attach images or files it uploads through Postiz and post to multiple channels in one request. You ask in plain language and Hermes runs the Postiz commands.

How do I connect Slack to Hermes Agent?

Install the Postiz Slack app into your workspace from the Postiz dashboard and invite it to the channels you want. Then install the Postiz skill in Hermes with npx skills add gitroomhq/postiz-agent and set POSTIZ_API_KEY. Hermes lists the Slack channel with postiz integrations:list and never needs a Slack token.

Is posting to Slack the same as chatting with Hermes Agent in Slack?

No. Hermes Agent's messaging gateway lets you talk to Hermes from Slack, Telegram, Discord, WhatsApp, or Signal. Posting to Slack through Postiz is Hermes publishing a scheduled message to a channel. You can chat with Hermes in one workspace and have it post updates into another.

How does Hermes Agent find the right Slack channel ID?

The channel setting expects an ID like C12345. Hermes fetches the channels available to the Postiz app through postiz integrations:trigger, matches the name you gave, and passes the ID. If the channel is missing, the app probably has not been invited to it yet.

Can Hermes Agent post to Slack on a schedule automatically?

Yes. Hermes Agent has a built-in cron scheduler. Run hermes cron create "weekdays at 8am" with a prompt such as "post today's standup reminder to #team via Postiz". Hermes runs the job unattended and delivers a confirmation to whichever chat you use with it.