How to post to X, LinkedIn and Bluesky from Claude

Claude is good at writing posts. The annoying part has always been what comes next: copying the text out, opening each network, pasting, trimming it to fit, picking a time. With an MCP connector, Claude can do that last step itself.

This guide sets that up with Postbase. By the end you'll be able to type something like "turn this blog post into an X thread and a LinkedIn post, and schedule both for Tuesday at 9am" and find both posts waiting in your calendar.

What you need

• A Claude account. Custom connectors work on every Claude plan, including Free (which allows one custom connector).
• A Postbase account with at least one channel connected. Every plan starts with a 7-day free trial.
• About five minutes.

You don't need an API key. Claude signs in to Postbase in a browser window, the same way you'd sign in to any app with Google.

Step 1: connect your social accounts to Postbase

Claude never talks to X or LinkedIn directly. It talks to Postbase, and Postbase posts to the networks you've connected. So connect those first: open Channels in Postbase and add each account.

X, LinkedIn, TikTok and YouTube use their own sign-in screens. Bluesky uses an app password, and Mastodon uses an access token from your instance. Either way, Postbase never sees your password.

Step 2: add Postbase as a connector in Claude

In Claude, open Settings → Connectors → Add custom connector. Name it Postbase and paste the server URL:

https://mcp.postbase.so/mcp

You can also copy it from the AI & API page in Postbase, which has setup instructions for each AI tool.

Step 3: sign in and pick a workspace

When you add the connector, Claude opens a Postbase sign-in window. Sign in and choose the workspace Claude can post to. If you manage several brands in separate workspaces, Claude only sees the one you pick here.

That's the whole setup. The connection now appears under AI & API → Connected apps in Postbase, where you can revoke it at any time.

Step 4: ask for a post

Start a new chat and make sure the Postbase connector is switched on in the chat's tools menu. Then ask in plain language:

Write an X post and a LinkedIn post announcing our new pricing page. Schedule the X one for tomorrow at 10am and the LinkedIn one for 11am.

Claude will usually check which channels you have, write the posts and then ask before it calls the tool that schedules them. It has ten tools to work with:

• list_channels tells Claude which accounts are connected, so it knows what "LinkedIn" means in your workspace.
• create_post saves a draft, or schedules a post or thread for a specific time, with images or a video attached.
• get_post checks how a post went on each channel: the live link, or why it failed.
• update_post edits or reschedules a post before it goes out.
• retry_post sends a post again to the channels where it failed.
• get_analytics shows how your posts did: likes, views, comments and shares.
• list_media finds images and videos in your Postbase media library, so Claude can attach them by name.
• add_media adds an image or video from a public link to your media library.
• list_scheduled shows what's already queued.
• cancel_post pulls a scheduled post back to a draft.

Getting a different version for each network

A single create_post call sends the same text to every channel you pick, unless it gives some channels their own. That's fine for a short announcement, but LinkedIn and X usually want different posts. Just ask for it:

Write a short X version and a longer LinkedIn version, and schedule them together.

Claude then gives each channel its own text in one post (channel_bodies), so both versions sit together on your calendar. The same goes for threads: ask for "a 5-post X thread" and Claude sends the posts as a thread, which Postbase publishes as a chain of replies.

Keep the character limits in mind, or ask Claude to: 280 per post on X, 300 on Bluesky, 500 on Mastodon and 3,000 on LinkedIn.

Checking what's scheduled

Everything Claude schedules lands in your Postbase calendar next to the posts you wrote yourself.

You can open any of them in the composer to change the wording, add an image or move the time. Or ask Claude:

What's going out this week? Cancel anything on Friday afternoon.

What Claude can't do (yet)

• Send files of its own. Claude attaches images and videos from your Postbase media library, so upload them there first. That's also how it schedules YouTube videos.
• Schedule TikTok posts. TikTok requires you to pick who sees each post yourself, so Claude can only save a TikTok draft for you to schedule in the composer.
• Schedule without an active plan. Drafts always work. Scheduling needs an active plan or trial.

Troubleshooting

Claude says it doesn't have a Postbase tool. Check the connector is switched on for this chat in the tools menu. Connectors can be enabled per conversation.

"One or more channel_ids are invalid". Claude guessed a channel id instead of looking it up. Ask it to list your channels first, then try again.

Claude is connected to the wrong workspace. Revoke the connection under AI & API → Connected apps, then remove and re-add the connector in Claude and pick the right workspace when you sign in.

Not using Claude's chat app?

The same server works in Claude Code, Cursor, VS Code, Windsurf and Gemini CLI. Each page has the one-line setup for that tool.