ChatGPT surfaces custom MCP servers under Plugins — renamed from Connectors in mid-2026 — and only with Developer Mode enabled. It is available on paid ChatGPT plans.
You will find your MCP URL on MCP → your server → How would you like to connect? → Connectors/Integrations/Plugins → ChatGPT. It looks like https://example.com/wp-json/acrossai/mcp.
Before you start
ChatGPT connects from OpenAI’s servers, so your site needs a public https:// address with a valid certificate. A local address such as mysite.local or localhost resolves only on your own machine. Developing locally? Use a tunnel such as ngrok or Cloudflare Tunnel, or connect once the site is live.
Step 1 — Turn on Developer Mode (one time)
- Sign in at chatgpt.com on a Business, Enterprise, Edu or Pro plan.
- Open Settings → Security and login and enable the Developer mode toggle. It is marked “ELEVATED RISK”.
On Business and Enterprise workspaces an admin must first turn it on under Workspace Settings → Permissions & Roles → Connected data → Developer mode. Until they do, the personal toggle will not appear.
Step 2 — Add the MCP server as a plugin
- Open Settings → Plugins, then click the + (New Plugin) button at the top right of the list.
- Paste your MCP URL into the MCP Server URL field.
- Set Authentication to OAuth. Leave Client ID and Client Secret blank — ChatGPT registers itself through Dynamic Client Registration. If you would rather issue the client yourself, use Generate credentials on the ChatGPT tab and paste the pair into those two fields.
- Tick the elevated-risk acknowledgment, then click Create.
Step 3 — Use it in a chat
This is the step people miss: adding the plugin does not switch it on for a conversation.
- Open a chat and click the + icon in the composer.
- Search for and select your new plugin.
- ChatGPT opens the browser OAuth flow the first time — approve the consent screen on your WordPress site.
The plugin stays available across future chats. If the row ever shows Reconnect, open Settings → Plugins and reconnect it.
Troubleshooting
There is no Developer mode toggle
Either the plan does not include it, or — on Business and Enterprise — a workspace admin has not enabled it yet. Developer mode is not available on the free plan.
“Could not reach the server” when creating the plugin
Open your MCP URL in a private window on another network — a phone on mobile data works well. If it does not load there, OpenAI cannot load it either. Check the certificate is valid, and that no firewall, basic-auth prompt or “coming soon” plugin stands in front of the site.
The plugin exists but ChatGPT never uses it
It has to be selected per conversation from the + menu in the composer. A plugin that is installed but not added to the chat is invisible to the model.
It connects, but there are no tools
Connecting and exposing are separate. Check the server’s Tools and Abilities tabs — a server with nothing exposed connects perfectly and offers nothing. Check Access Control too: a user who is not allowed on this server receives an access-denied response despite a valid connection.
It worked, then stopped
If your site address changed — a move to HTTPS, a new domain, dropping www — existing authorizations were issued for the old address and are refused until the client authorizes again. Reconnect from Settings → Plugins.
Another MCP plugin is installed
Two MCP plugins on one site can publish competing OAuth endpoints, and clients may pick the wrong one. If connections fail for no other visible reason, deactivate the others and try again.