postmoderno

blog · by Artem Senenko · · 3 min read

How to schedule social media posts from ChatGPT or Claude

Connect postmoderno to ChatGPT, claude.ai, Claude Code or Cursor, then schedule posts to Bluesky, Mastodon and X by asking for them in the chat. About five minutes, on the free plan.

ChatGPT and Claude can already write your posts. With postmoderno connected, they can also schedule them, and the posts go out on Bluesky, Mastodon or X at the time you asked for. Setup takes about five minutes and fits in the free plan.

You need:

  • a postmoderno account (free, no card)
  • an account on Bluesky, Mastodon or X
  • ChatGPT, claude.ai, Claude Code, Cursor or another MCP client

1. Create an account

Open postmoderno.io and sign in with your email address. postmoderno mails you an eight-digit code and a link, and either one signs you in. You have no password to set.

2. Connect the accounts you post to

In the app, open connections and pick a network.

  • Bluesky asks for your handle and an app password. Create one in Bluesky under Settings → Privacy and security → App passwords. postmoderno posts with it in place of your real password, and you can revoke it from Bluesky whenever you like.
  • Mastodon asks for your instance, such as mastodon.social, and sends you there to approve.
  • X sends you to x.com to approve. X charges for every post, so X posts draw on a prepaid wallet. The pricing page shows how far each plan and pack goes.

3. Connect your agent

ChatGPT and claude.ai sign in to postmoderno with OAuth, so you paste no key. Claude Code, Cursor and other clients use a key you create in the app.

ChatGPT

Open Plugins → Add custom MCP server and fill in:

Name  postmoderno
URL   https://mcp.postmoderno.io/mcp
Auth  OAuth

ChatGPT warns you about custom servers. Accept, and it sends you to postmoderno to sign in and choose what ChatGPT may do: see your connected accounts, write, edit and schedule posts, and read or update your notes on how you write. Deleting posts starts switched off, and you can switch off anything else you would rather keep to yourself. Press allow, then in a chat type @postmoderno and pick it.

If you don’t see the option to add a server, your ChatGPT plan or workspace may not allow custom servers, or an admin may need to switch them on.

claude.ai

Open Settings → Connectors → Add custom connector and paste:

https://mcp.postmoderno.io/mcp

Claude sends you to postmoderno to sign in and allow it, the same way ChatGPT does.

Claude Code

In the app, open mcp access and press New key. Pick what the key may do and, if you like, which accounts it may post to. Copy the key: the app shows it once. Then run:

claude mcp add --transport http postmoderno https://mcp.postmoderno.io/mcp \
  --header "Authorization: Bearer YOUR_TOKEN"

Cursor and other MCP clients

Create a key the same way, then add postmoderno to your mcp.json:

{
  "mcpServers": {
    "postmoderno": {
      "type": "http",
      "url": "https://mcp.postmoderno.io/mcp",
      "headers": { "Authorization": "Bearer YOUR_TOKEN" }
    }
  }
}

4. Schedule your first post

Ask the way you would ask a person:

Schedule “We just shipped dark mode” on Bluesky and Mastodon for tomorrow at 9am.

The agent drafts the post, checks it with you and schedules it. postmoderno answers with the time it understood, in your timezone and in UTC, and a good agent repeats it back:

Scheduled for tomorrow, 09:00 your time (07:00 UTC), on Bluesky and Mastodon.

A few more requests to try:

  • “Turn these release notes into a thread for X and one longer post for Mastodon, both Tuesday at 14:00.”
  • “What goes out this week?”
  • “Move tomorrow’s post to 10:30.”
  • “Remember that I write short sentences and never use hashtags.”

postmoderno stores that last kind of note, so the agent you connect next week, or the other client on your phone, writes the same way.

If something goes wrong

The agent doesn’t seem to know postmoderno

In ChatGPT, pick it with @postmoderno in the chat. In other clients, check that the server shows as connected in the client’s settings.

A post failed

Ask your agent “why did that post fail?”. postmoderno keeps a record of every publish attempt, so the agent can tell you the cause, and whether it can fix the problem or you have to.

A connection dropped

You may have revoked a Bluesky app password, or signed out of an app on the network’s side. Open connections in the app and connect the account again.

Where to go next

If running a scheduler through an agent is new to you, What an MCP post scheduler is explains the model and when it suits you. The about page covers what postmoderno takes care of, and pricing lists the plans.

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