Connect ChatGPT
ChatGPT connects to remote MCP servers as custom connectors. To add a custom connector that exposes general-purpose MCP tools, you need to enable Developer Mode on your ChatGPT account. Once enabled, paste the gateway URL into ChatGPT's connector settings and complete the OAuth flow.
ChatGPT's general-purpose custom-connector support runs through Developer Mode, which is available on Pro, Team, Enterprise, and Edu plans. Before Developer Mode shipped, connector support in ChatGPT was limited to read-only Deep Research connectors. Use Developer Mode to expose the full range of tools the Zuplo MCP Gateway provides.
Prerequisites
- A Zuplo project with the MCP Gateway plugin configured and at least one MCP route. See the quickstart if you haven't set one up yet.
- A ChatGPT Pro, Team, Enterprise, or Edu subscription.
- Developer Mode enabled on your ChatGPT account. The toggle lives in Settings → Connectors → Advanced (the exact location varies by plan; see OpenAI's Apps SDK documentation for current instructions).
Get the route URL
Each MCP route in config/routes.oas.json is reachable at
https://{deploymentUrl}/{routePath} once deployed — for example
https://{deploymentUrl}/mcp/linear-v1.
Add the connector
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Open Connectors settings in ChatGPT.
In the ChatGPT web app, open Settings → Connectors.
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Add a custom connector.
Click the option to add a custom connector. Depending on your plan, this may be Add custom connector, Create, or Advanced → Add MCP server.
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Enter the gateway URL.
Paste the route URL. Give the connector a name and description — these are what ChatGPT shows in the conversation interface.
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Authenticate against the gateway.
Save the connector. ChatGPT opens the gateway's OAuth flow. Sign in with the identity provider you configured for the gateway.
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Complete the upstream connection.
The gateway shows a consent page with the upstream MCP server the route proxies to. Click Connect next to the upstream, complete its OAuth flow, then click Authorize to finish.
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Enable the connector for chats.
Back in ChatGPT, enable the connector for the conversations or assistants where you want it active. Tools from the gateway then appear when ChatGPT needs them.
What ChatGPT supports
ChatGPT registers itself with the gateway through Dynamic Client Registration (DCR) and the newer Client ID Metadata Documents (CIMD) flow. It supports:
- Tools — invoke gateway-exposed tools from the conversation.
- MCP Apps — render interactive HTML widgets inline. This is the same surface that powers the OpenAI Apps SDK, which is built directly on top of MCP Apps.
ChatGPT doesn't currently consume prompts, resources, roots, sampling, or elicitation from a remote MCP server.
Build an Apps SDK app on top of the gateway
If you're authoring an MCP server intended to render rich UI inside ChatGPT,
read OpenAI's Apps SDK documentation
— the Apps SDK builds on the MCP Apps extension, so an Apps SDK app is an
MCP server with UI conventions on top. The Zuplo MCP Gateway forwards
Apps-related metadata (_meta.ui.*) from upstream MCP servers unchanged. Tool
authors who want to ship UI to ChatGPT should follow the Apps SDK guide; the
gateway transparently relays the additional metadata to the client.
For more background on Apps SDK and Zuplo-hosted MCP servers, see OpenAI Apps SDK with Zuplo.
Troubleshooting
- "Custom connector" option isn't visible. Confirm your plan supports Developer Mode (Pro, Team, Enterprise, or Edu) and that Developer Mode is enabled in your settings.
- Sign-in succeeds but no tools appear. Tools only appear when ChatGPT decides to invoke them. Try a prompt that mentions the action you want to take. If the connector itself is disabled in a conversation, ChatGPT doesn't see any of its tools.
- OAuth fails with a redirect error. ChatGPT registers its redirect URI dynamically. The gateway accepts dynamic registration by default. If you've locked down DCR on your identity provider, switch to a provider that supports DCR, or pre-register an OAuth app for ChatGPT.
Related
- Connect MCP clients overview
- OpenAI's Apps SDK documentation
- OpenAI Apps SDK with Zuplo
- Authentication overview