Any MCP client + PostOnce

Give your AI agent the tools to publish

Connect an MCP-compatible agent to PostOnce to discover your social accounts, publish posts, and set up automatic crossposting.

Connect your agent

Requires a PostOnce account, API access, and your own API key.

See setup steps

Set up your connection

Connect your agent to PostOnce

Use your own PostOnce API key.

1
Prepare your PostOnce account
You need API access on your plan and at least one connected social account. Create a dedicated key with accounts:read for your first check; add posts, media, or workflow scopes only for the actions you want.
Create an API key Connect social accounts Check plan access
2
Configure a Streamable HTTP connection
Your client must support Streamable HTTP and a custom Authorization header. Enter the endpoint and replace the placeholder with your key in its private connection settings. Clients that require OAuth need a separate supported setup.
Connection details · adapt to your client
```
URL: https://postonce.to/mcp
Transport: Streamable HTTP
Authorization: Bearer YOUR_POSTONCE_API_KEY
```
Follow the client-specific instructions above. Keep your API key out of agent conversations and public files.
3
Check the connection
Refresh your client’s tools and ask it to show your connected social accounts. An empty account list means you still need to connect accounts in PostOnce.
Try this prompt
Show my connected social accounts.
Expect account names, platforms, and IDs from list_active_accounts. Choose actual accounts before asking the agent to publish.

Read the connection documentation

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 your API key’s scopes and 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 a plan with Public API access. Your API keys tab checks your account’s actual entitlement and shows an upgrade option when required. Connecting a client does not change your plan.

What if my agent shows no social accounts?

Connect or reconnect a social account in PostOnce, then ask the agent to list active accounts again. The API key must belong to the same PostOnce account and include accounts:read.

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 replace the key?

Revoke the dedicated API key in Preferences → API keys and remove the server from your client. To reconnect, create a new key with the scopes you need and replace the old key in the client’s private configuration.