X (Twitter) + PostOnce
X (Twitter) MCP Server
X (Twitter) MCP server for Claude, ChatGPT, Cursor and Codex. Your AI agent can write, post and schedule tweets with images, a GIF or a video through X's official API, with no scraping, no browser automation and no X developer account.
Requires a PostOnce account, API access, and your own API key.
https://postonce.to/mcpWhat your agent can do on X (Twitter)
Publish a tweet now (up to 280 characters, or 4,000 if the account had X Premium when you connected it)
create_post on your connected X account
Schedule a tweet for later
create_post with publish_at
Post up to 4 images, or 1 GIF, or 1 video (up to 2 minutes without Premium)
create_upload_url, upload, then create_post with media
Save a draft to finish later
create_draft
Check whether a tweet went out, and get its URL
get_post
Change or cancel a scheduled tweet
update_post, cancel_post
Post the same thing to X and other platforms
Add more targets to create_post (LinkedIn, Instagram, TikTok, YouTube, Threads, Facebook, Pinterest, Bluesky)
Not supported: threads as reply chains, replies, quote posts, polls, reading your timeline or mentions, analytics, DMs, and editing or deleting tweets that are already published. Text over the character limit is cut off, not rejected, so keep each post within it. This server publishes; it doesn't browse X for you.
Connect X (Twitter) to your agent
You need a PostOnce account with your X (Twitter) account connected. Try it free for 7 days without entering a card.
Claude and ChatGPT
Add a custom connector with this URL and sign in with PostOnce. No API key.
https://postonce.to/mcpClaude Code
Install the plugin for the connection and the X (Twitter) skills, then set POSTONCE_API_KEY.
claude plugin marketplace add postoncehq/plugins
claude plugin install x-mcp@postoncehqCursor, Codex and other clients
Point any MCP client at the URL above over Streamable HTTP with the header Authorization: Bearer and your PostOnce API key. Never paste the key into chat.
X (Twitter) skills included
The plugin ships these Agent Skills so your agent knows what works on X (Twitter) before it posts. They work in Claude Code, Codex, Cursor and any client that reads Agent Skills.
- x-tweet-generator
Writes single tweets in your voice: a first line that earns the stop, one idea, within 280 characters (or 4,000 for Premium accounts).
- x-thread-generator
Turns a topic, blog post or transcript into a 5–15 post Twitter thread, then gives you a way to publish it that actually works with this server.
- x-bio-generator
Writes a 160-character X (Twitter) bio, display name and pinned tweet idea for you to paste into your profile.
- x-tweet-formatter
Formats tweets: line breaks, Unicode bold and italic (with their accessibility and search costs), and splitting text that's over the limit.
- x-content-calendar
Plans 1–4 weeks of tweets from your goals or a source you want to repurpose, drafts each one and schedules them on approval.
- postonce
Publishing workflow: pick the right account, upload media, schedule, and confirm the post actually went live.
Try these prompts
Turn this blog post into a tweet with the chart attached and post it tomorrow at 10am.
Write five tweet options about our launch and schedule the best one for 9am.
Plan a week of tweets from this podcast transcript and schedule one a day.
X (Twitter) MCP questions
Is there an official X (Twitter) MCP server?
This server uses X's official API through PostOnce, with the OAuth permissions you grant when you connect. You don't need your own X API access.
Can Claude post tweets?
Yes, once it's connected to an MCP server that can publish, like this one. Claude writes the tweet, then calls create_post. It can post now or schedule for later.
Is it safe for my X account?
Yes. Tweets go through X's official API with the permissions you grant when you connect. Many Twitter MCP servers on GitHub drive a logged-in browser session or call unofficial, scraped endpoints instead, which X's terms don't allow and which can get accounts restricted or suspended.
Do I need an X developer account or API key?
No. PostOnce holds the X API access; you just connect your account.
Can it post Twitter threads?
Not as a reply chain. The x-thread-generator skill still writes the thread, then offers three ways to ship it: publish the first post and paste the rest as replies yourself, collapse it into one long post if your account has X Premium, or schedule the parts as standalone tweets over several days.
Can it post long tweets?
Yes, up to 4,000 characters if your account had X Premium (blue check) when you connected it to PostOnce. Otherwise the limit is 280. If you subscribe to Premium later, reconnect the account.
Is it free?
The skills are free and MIT-licensed on GitHub. Publishing runs through a PostOnce account, which you can try free for 7 days without entering a card. After that, see pricing.
MCP servers for other platforms
The same connection publishes everywhere PostOnce supports. Each platform has its own skills: LinkedIn MCP, Instagram MCP, TikTok MCP, YouTube MCP, Facebook MCP, Threads MCP, Bluesky MCP, Pinterest MCP.
Let your agent post to X (Twitter)
Requires a PostOnce account, API access, and your own API key.