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Post to Mastodon with Claude ยท 2026

Post to Mastodon with Claude

Mastodon has no single API to sign up for. Every instance is its own server with its own app registration, its own tokens, and its own limits. RobinReach handles that per-instance setup once, so Claude can write and schedule your posts through one MCP URL, whichever server you call home.

Connect Claude Free See the 3-Step Setup
  • No Mastodon API setup
  • No code, one MCP URL
  • Works with ChatGPT and Codex too
The DIY route

One network, thousands of servers

The Mastodon API is a pleasure to read and a chore to run.

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Every instance is a new integration

There is no central developer portal. You register an application on your own server, collect a client id and secret, and repeat the whole dance for every instance you post from.

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Media that is not ready yet

Upload a video and Mastodon accepts it, then keeps processing it in the background. Attach it too early and the post fails. You have to poll until it is done.

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No scheduling in the app

Mastodon itself has no post scheduler for normal accounts. Anything time-based means writing a job runner and keeping it alive.

Why the bridge matters

Why Claude can't post to Mastodon on its own

Claude writes brilliant posts, but out of the box it has no account access, no publishing rights, and no scheduler. RobinReach's MCP server is the missing pair of hands.

Claude by itself

  • Cannot log in to Mastodon or hold OAuth tokens for your account.
  • Cannot publish, schedule, or upload media. The draft dies in the chat window.
  • The workaround is the Mastodon API: developer registration, reviews, token refresh, and format rules, all maintained by you.
  • You end up as the copy-paste middleman for every single post.
The one-connector fix

Claude + RobinReach over MCP

  • RobinReach holds the official, compliant Mastodon connection. You authorize it once with a normal OAuth click.
  • One MCP URL gives Claude real tools: draft, validate, attach media, schedule, and publish.
  • RobinReach handles tokens, rate limits, media processing, and Mastodon's format rules for you.
  • The same connector covers all 13 RobinReach networks, so one setup unlocks every channel.
3-minute setup

Connect Claude to Mastodon in 3 steps

No developer account, no app review, no code. If you can paste a URL, you are qualified.

  1. 1

    Copy your MCP URL

    Create a free RobinReach account and connect Mastodon with one OAuth click. Your personal MCP URL is waiting in workspace settings.

  2. 2

    Paste it into Claude

    In Claude, open Settings, then Connectors, and add RobinReach as a custom connector. On Claude Desktop you can paste the config block instead. The same URL also works in ChatGPT and Codex.

  3. โœ“

    Say "Hi Robin"

    Claude discovers RobinReach's tools on its own. Ask it to write and schedule your first Mastodon post and watch it appear on your calendar.

claude_desktop_config.json 
{
  "mcpServers": {
    "robinreach": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "https://robinreach.com/mcp/v1/messages?api_key=YOUR_API_KEY"
      ]
    }
  }
}

Using claude.ai or the Claude mobile app? Just paste your MCP URL under Settings, then Connectors, then Add custom connector. Full instructions for every AI client are on the AI setup guide.

A real conversation

What posting to Mastodon from Claude looks like

You describe the outcome in plain language. Claude uses RobinReach's tools to do the rest.

Claude connected to RobinReach
Robin, post a release note to Mastodon tomorrow at 9: we shipped Mastodon support. Keep it human, no marketing voice, and add a reply with the three things it can do.
validate_post: 500 character limit checked for the instance
create_post: status scheduled for 09:00
create_post: reply queued to follow the main status
Scheduled. The main post reads like a person wrote it, not a changelog, and the reply lists the three capabilities as a short chain underneath. Both go out tomorrow morning on your instance.

More example prompts for planning, writing, and scheduling live on the AI setup guide.

Full Mastodon coverage

Everything Claude can publish on Mastodon

RobinReach exposes Mastodon's formats and rules to Claude as tools, so posts come out platform-native, not copy-pasted.

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Text posts

Conversational posts inside the 500 character limit, written for an audience with no algorithm to game.

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Image posts

Up to four images per post, uploaded and attached with the processing wait handled for you.

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Video posts

One MP4 or WEBM per post, uploaded and held until the instance finishes transcoding it.

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Reply threads

Up to ten connected replies under the main status, each with its own image if you want one.

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Any instance

mastodon.social, your company server, or a niche community. Connect the domain and RobinReach does the rest.

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Real scheduling

Mastodon has no built-in scheduler. Claude plus RobinReach gives you one, driven by plain language.

FAQ

Posting to Mastodon with Claude, answered

How do I post to Mastodon with Claude?
Create a free RobinReach account, connect Mastodon by entering your instance domain, and paste your RobinReach MCP URL into Claude under Settings, then Connectors. Then ask Claude to write and schedule Mastodon posts and it publishes through RobinReach.

Which Mastodon instances are supported?
Any instance running the standard Mastodon API. You enter the domain, approve the connection on your own server, and RobinReach registers the application for you behind the scenes.

Can Claude post threads on Mastodon?
Yes. Claude drafts the main status and up to ten connected replies, and RobinReach publishes them in order at your scheduled time. Every reply can carry its own image.

What is the character limit?
500 characters on a default Mastodon install, which is what RobinReach validates against. Some instances raise that limit, so treat 500 as the safe number to write to.

Can I attach images and video?
Yes. Up to four images per post, or a single MP4 or WEBM video up to 40MB. RobinReach waits for the instance to finish processing media before it publishes, so posts do not fail halfway.

Does Mastodon have a built-in scheduler?
No. Regular Mastodon accounts have no scheduling feature, which is exactly why pairing Claude with RobinReach is useful: planning, writing, and scheduling happen in one conversation.

Can I use ChatGPT instead of Claude?
Yes. The same RobinReach MCP URL works in ChatGPT connectors and OpenAI Codex, so the identical workflow runs from any assistant.

Keep exploring

Mastodon icon

Mastodon Scheduling

See how RobinReach connects any Mastodon instance and schedules posts, images, and reply threads alongside your other networks.

Explore the scheduler

Post with Claude on every network

One connector covers LinkedIn, X, Instagram, TikTok, and more. See every platform Claude can publish to.

All AI integrations

The full AI setup guide

Step-by-step instructions for Claude, ChatGPT, Codex, and the API, plus every MCP tool RobinReach exposes.

Open the guide

Comparing AI posting tools for Mastodon?

RobinReach vs Buffer RobinReach vs Publer RobinReach vs Blotato

Give Claude publishing hands on Mastodon

Free account, one OAuth click, one MCP URL. Your first AI-scheduled Mastodon post is about three minutes away.

Start Free Review the Setup