How to Use posterly with Hermes: YAML MCP to First Approved Schedule

Hermes is already your terminal agent. You do not want to leave it to open a social dashboard. That is what a YAML mcp_servers block is for.

Claude Desktop and Cursor use JSON mcpServers. Hermes uses YAML mcp_servers (underscore). After any edit you run /reload-mcp inside a chat session. You do not restart the whole agent. There is also a catalog picker (hermes mcp) and hermes mcp install <name> for catalog names. posterly is a custom server you add yourself.

This is a new-user walkthrough, from config.yaml to the first approved schedule. The long encyclopaedia is the Hermes guide. Fields sit on poster.ly/hermes.

Two layers, one YAML file

• Hermes is the agent. Config lives at ~/.hermes/config.yaml. You can keep the key in ~/.hermes/.env as ${POSTERLY_API_KEY}.
• posterly is accounts, media, the queue. Buy Starter + API in one checkout ($10 a month). Agency API is $29 a month on Agency. See pricing.

Local stdio can read a real file_path. Hosted HTTP cannot. Chat attachments never reach MCP.

1. Edit config.yaml, then /reload-mcp

Add a posterly block under mcp_servers. Point it at stdio (npx -y posterly-mcp-server@latest plus POSTERLY_API_KEY) or at https://www.poster.ly/api/mcp with a bearer header.

Then, inside a Hermes chat:

/reload-mcp

If you skip reload, Hermes keeps talking to the old server list and you will swear the key is wrong.

If you do not have a key yet:

You: Set up posterly as my social scheduling agent. I do not have an account. Do not post anything.

Hermes: Confirm the email. You pay and set a password in the browser. I will not take the card.

2. Agent-led signup (you still pay in the browser)

start_signup, checkout, get_signup_session, password in posterly, then paste pst_live_... into YAML or .env. Same contract as agent signup.

Then:

You: Run whoami. Do not post.

Hermes: Authenticated. No social accounts yet.

If this fails after a YAML edit, you probably did not /reload-mcp.

Founder newsletter

Launch with Alex

Building companies from Dubai. Field notes from running more than one, and the decisions that paid off.

Join the list (opens in a new tab)

3. First connect session

create_connect_session, you open connect_url, provider consent, poll until connected. 30 minutes. Manual networks wait in posterly, not in the Hermes thread.

4. Media: prefer file_path on this machine

Hermes on your laptop can upload_media with file_path. That path bypasses the Vercel ~4MB JSON body. Hosted-only Hermes should use create_signed_upload then PUT, or create_media_drop then list_media. Details: Solving the 4MB MCP limit.

5. Draft, validate, then say send

1. Draft.
2. validate_post.
3. Preview.
4. You confirm that exact post.
5. create_post with confirm: true.

You: Draft a LinkedIn post for Thursday 10:00 UK. Validate. Do not create.

Hermes: validate_post passed. No row yet.

You: Schedule it.

Hermes: Scheduled. View in Posterly: [link]

hermes mcp install is for catalog names. It is not a substitute for YAML if posterly is not in that catalog yet.

posterly

Schedule smarter with AI

AI captions, 18 platforms, plans from $7/mo

Start Free TrialSee how it works

6. After the first post

create_posts_batch, get_learned_voice, get_account_analytics. Reload MCP whenever you rotate a key.

7. Where this usually breaks

• Edited YAML, skipped /reload-mcp. Classic.
• Copied Cursor JSON. Hermes wants YAML mcp_servers.
• Paperclip. Use file_path or create_media_drop.
• Skipped confirm. Tool refuses.
• Stale OAuth. New session.

Start with config.yaml

Paste a block from the MCP setup guide, /reload-mcp, walk agent signup if you are new, then approve one validated post. The short Hermes setup page has the YAML shape.

You keep the agent. posterly keeps the queue. Nothing publishes until you say send.