ChatGPT + PostOnce

Turn a ChatGPT conversation into a social post

Connect ChatGPT 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 connection in ChatGPT. No PostOnce API key is needed. You can check accounts before connecting a social account; publishing needs a connected destination and ChatGPT write-tool access. This is manual setup, not an approved directory listing.

See setup steps

Set up your connection

Connect ChatGPT to PostOnce

Before you connect

Use ChatGPT on the web with permission to add a custom MCP connection. Publishing also requires write-tool access in your ChatGPT plan and workspace; a read-only connection cannot publish posts. Workspace administrators may need to enable access. Workspaces requiring verified email-domain restrictions are not supported by this setup.

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 ChatGPT availability

1
Add a custom connection in ChatGPT
First open ChatGPT Settings → Security and login and enable Developer mode. Then open the Plugins page and select Create app (or the plus button). In New Plugin, enter PostOnce as the name and use the connection details below. Developer mode must be enabled before creating this custom connection.
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
Select OAuth authentication and automatic client registration (DCR) when asked. Keep client ID and client secret empty for automatic registration. PostOnce handles sign-in in your browser; no PostOnce API key is entered in this form.
Open ChatGPT
My account shows Apps settings
If your account shows Apps instead of Plugins, enable developer mode using the controls available to your account or workspace. Open Settings → Apps → Create (workspace administrators can use Workspace settings → Apps → Create). Enter the same endpoint, choose OAuth, select Scan Tools, complete authorization, and then select Create. Availability and write permissions depend on the workspace rollout.
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.
Complete the connection and review its Actions. If PostOnce shows Connected but no actions, select Refresh and wait for the actions to appear. Start a new chat, open the + picker, search for PostOnce, and select it so the PostOnce pill appears in the composer 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

Reconnect or revoke access

If authorization expires, is canceled, or fails, return to ChatGPT 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 ChatGPT 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 ChatGPT’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.