Claude + PostOnce

Turn a Claude conversation into a social post

Connect Claude to PostOnce to find your social accounts, prepare drafts, and publish content you approve.

Requires PostOnce Creator or Pro and permission to add a custom OAuth connector in Claude. No PostOnce API key is needed. You can check accounts before connecting a social account; publishing needs a connected destination. This is manual setup, not an approved directory listing.

See setup steps

Set up your connection

Connect Claude to PostOnce

Before you connect

Use Claude’s web or desktop remote-connector interface, with permission to add a custom connector. For a Team or Enterprise workspace, its owner must first add the connector for members. This setup is for Claude’s remote connector, separate from Claude Code’s local MCP configuration.

You need PostOnce API access on your plan. Your actual entitlement is checked when you authorize access. You can connect the assistant and check your accounts before connecting a social account; a connected social account is required to publish.

Connect social accounts Check PostOnce plans Check Claude availability

1
Add a custom connection in Claude
Open Customize → Connectors and choose Add custom connector. Enter PostOnce as the name and the remote server URL below, then select Continue to discover the server. If asked for a connector type, select Web. Workspace owners add it through Organization settings → Connectors → Add → Custom.
Remote MCP server URL
```
https://postonce.to/mcp
```
Name
PostOnce
Description
Publish posts and manage automatic crossposting with your connected PostOnce accounts.
Authentication
OAuth · automatic client registration
In the second step, keep Authentication set to Sign in now. Under OAuth client, select Register automatically instead of the default Use Claude’s published identity (Recommended). This selects automatic registration (DCR). If your dialog uses the earlier labels, choose Always required and No client ID — register one automatically. In the earlier one-screen dialog, leave the optional OAuth client ID and secret empty. No request header or API key is needed.
Open Claude
2
Sign in and review access
The connection opens PostOnce’s sign-in and consent flow on postonce.to. Check the signed-in account, app name, return destination, and listed permissions. Select Allow access to continue, or Cancel to stop. A plan restriction must be resolved in PostOnce before authorization can complete.
Select Add to create the connector, then select Connect to sign in when prompted. In a new chat, open the + menu, choose Connectors, and enable PostOnce before trying the account prompt below.
3
Verify with an account check
Try this prompt
Show my connected social accounts.
Look for a PostOnce tool result with your actual account names and IDs. A successful empty result confirms the account check worked, but there are no connected accounts to publish to. Connect a social account in PostOnce before publishing, then ask again. Adding the server alone does not prove authorization or publishing succeeded.
Choose your accounts and confirm the intended post before publishing. Inspect its returned post ID and each destination’s status; queued does not mean delivered.
Review published posts
4
Create and review an unpublished draft
First image draft
Create an unpublished PostOnce draft with the caption "Trying my first Claude draft" and this public PNG image: https://postonce.to/integrations/assets/postonce-transparent.png. Leave destinations empty and do not schedule or publish it. Return the draft ID, then get that draft and show me its saved caption, image, and status for review.
Check that the returned draft stays in your inbox with the image, caption and no destinations. You can review it in PostOnce before choosing accounts or publishing. This example uses a public image URL; it does not upload a Claude chat attachment.
Review your drafts in PostOnce

Reconnect or revoke access

If authorization expires, is canceled, or fails, return to Claude and start its Connect flow again. To disconnect, open Preferences → AI agents → Connected apps in PostOnce and revoke the matching app. Remove the connector from Claude as well if you no longer want it listed.

The hosted connection cannot read a path on your computer or assume access to a chat attachment. Use a supported public media URL or a documented client upload flow.

Read Claude’s connection instructions

From connection to first result

Start with one useful action

Find your accounts

Try this prompt

Show my connected social accounts.

Use the returned names and IDs to choose your targets. If nothing appears, connect an account in the dashboard.

Publish an update

Try this prompt

Help me publish a product update. First show my connected accounts, then ask me to choose the destinations and confirm the exact text before publishing.

After creation, ask for the post ID and each destination’s delivery status. A queued post is still waiting to publish.

Set up crossposting

Try this prompt

Show my connected accounts and the available crossposting options. Help me choose a supported source and destinations, then confirm the workflow before creating it.

A created workflow applies to future matching source posts. Inspect the workflow in PostOnce before relying on it.

Review posts in PostOnce Review crossposting workflows

Know what your agent can access

Connected accounts and scoped actions

PostOnce uses the permissions you approved during consent and your existing account permissions. Your available destinations come from your connected accounts; media and text requirements still vary by platform.

Media needs a supported upload path

The hosted server cannot read a file path on your computer or assume access to a chat attachment. For a first media post, use a supported publicly accessible media URL and have the agent validate the selected platform’s requirements before publishing.

Media post example

Help me publish an image from a public media URL. Ask me for the URL, text, and connected destination accounts; check the platform requirements and confirm the post before creating it.

Questions before connecting

Do I need a particular PostOnce plan?

You need PostOnce API access on your plan. Your entitlement is checked during sign-in and consent. Connecting an assistant does not change your plan.

What if my agent shows no social accounts?

A successful empty account result means the connection worked. Connect or reconnect a social account in PostOnce before publishing, then ask again. Check that you authorized the intended PostOnce account and accounts:read permission.

How do I check a failed or queued post?

Ask the agent to get the post using its returned ID and inspect each target’s status and error. Review the post in the dashboard. Check the existing result before creating another post to avoid duplicates.

How do I disconnect or reconnect?

Revoke the matching app in Preferences → AI agents → Connected apps and remove the connection from your assistant. To reconnect, start its Connect flow again and review the requested permissions.