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 Developers page in Postbase, which has setup instructions for each AI tool.
Use your API key to automate Postbase — hook up an AI agent over MCP, script it from the CLI, or call the REST API directly.
API keys
A key authenticates the MCP server, the REST API, and the CLI. Shown once — store it safely.
pb_live_…9c1eMCP client configuration
Connect the Postbase MCP server to your AI tool so it can schedule and publish for you.
Authentication
No key to manage — your tool signs in through Postbase.
Client
In Claude: Settings → Connectors → Add custom connector, and paste this URL. You'll sign in to Postbase in a browser window — no API key.
https://mcp.postbase.so/mcpAdd to ClaudeCopyConnected apps
Tools you've signed in to Postbase from. Revoking cuts off their access immediately.
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 Developers → 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 four tools to work with:
list_channelsSee connected accounts and their platforms.create_postDraft or schedule a post/thread to any channels.list_scheduledReview what's queued to publish.cancel_postPull a scheduled post before it goes out.- 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.
- 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. 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, then schedule them separately.
Claude then calls create_post once per network, each with its own text. 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)
- Attach images or video. The connector sends text posts and threads. To add media, ask Claude to save a draft, then attach the image or video in the Postbase composer.
- Post to TikTok or YouTube on its own. Both need a video, so Claude can draft the caption but you add the video before it's scheduled.
- 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 Developers → 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.
Postbase