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2026-09-29 • 6 min read • Connect

How to Connect an MCP Server to ChatGPT

Connect a hosted MCP server to ChatGPT on the web with developer mode, check that its tools load, and ask your first grounded question.

To connect an MCP server to ChatGPT on the web, turn on developer mode under Settings, then Security and login. Then go to Plugins, select the plus button, and paste the server's URL with no authentication. Start a new chat, choose Developer mode from the plus menu, and select your app. MCP Studio by Appa Tools builds that server from your docs, a GitHub repository, or files without any code.

By the end of this guide, ChatGPT will answer from your own material. You will have checked the tool list, asked a question you know the answer to, and seen ChatGPT cite the page it came from.

What ChatGPT needs from an MCP server

ChatGPT connects to MCP servers through developer mode, which turns a server into an app you can pick in any conversation.

A server you reach by URL. ChatGPT runs in your browser, so the server has to live at a public HTTPS address rather than on your laptop. MCP Studio hosts yours, so there is nothing to install or keep running.

No token to paste. ChatGPT signs in to a server with OAuth or connects with no authentication. An MCP Studio server set to public connects with no authentication, which is the option you choose below.

Tools ChatGPT can call. When you create the app, ChatGPT asks the server what it can do and lists the tools it found, such as search_docs or ask_question. In a conversation it calls them whenever the question needs your material. Every MCP Studio tool only reads; none of them changes anything.

Build the server in MCP Studio

Take a real example. Harborline is a ferry operator with a public brand kit: colors, voice rules, the people it writes to, customer facts like terminals and refunds, and a ready-made welcome email. You want ChatGPT to draft a customer email or a booking page headline in that voice without pasting the kit into every chat.

  1. Open the MCP Studio wizard. You do not write any code, and the wizard takes about a minute.
  2. Name it for the job. Harborline brand tells you later what the server is for.
  3. Add the source. Paste a documentation URL, a website, or a GitHub repository, or upload a PDF, a spreadsheet, or an image. For Harborline, that is the brand kit repository.
  4. Choose the tools. Pick at least three. Search and question answering cover most conversations, and the tool selection guide explains the rest.
  5. Keep the server public, deploy, then copy the server URL from the setup page. It looks like this:

https://appatools.com/mcp-studio/api/mcp/your-server-name

The endpoint exists straight away, and indexing continues in the background. Give a large site a few minutes before you judge the answers.

Add the server to ChatGPT

Developer mode is available on Plus, Pro, Business, Enterprise, and Education plans. On a Business, Enterprise, or Education workspace, an admin turns it on for the workspace first.

  1. Turn on developer mode. Open Settings, select Security and login, and turn on Developer mode.
  2. Create the app. Go to Plugins and select the plus button. Enter a name, such as Harborline brand, and a short description of what the server knows.
  3. Add the connection. Paste the server URL and choose No authentication.
  4. Create it, then review the tools. ChatGPT lists the tools it found on the server. If the list is empty, see the troubleshooting section below.

The app appears under Drafts in your app settings. OpenAI's connect and test guide has screenshots of each screen.

Check that it works

Start a new chat and pick the app. Open the plus menu, choose Developer mode, and select Harborline brand.

Ask something you know is in the source. Naming the app helps ChatGPT choose its tools over a web search:

Use the Harborline brand app to write a two sentence welcome message for a first time ferry passenger.

ChatGPT asks before it runs a tool. Review the request and approve it, and you can remember that choice for the rest of the conversation. Then compare the specifics rather than the tone: that Harborline runs ferries, a phrase from the voice rules, a color name like Hull Navy. Each passage carries a link to the page it came from, and you can expand the tool call to see exactly what the server returned.

Then ask something the source does not cover. When nothing in your content is a real match, the server says so first, and ChatGPT passes that on instead of filling the gap from general knowledge.

You: What is Harborline's parental leave policy?

ChatGPT: The Harborline server does not have anything on parental leave. Its content covers the brand colors, voice, audiences, and customer facts.

One known answer and one deliberate miss tell you the connection is doing its job.

If the tools do not appear

The plus button does not offer a new app. Developer mode is off, or your workspace admin has not allowed it.

ChatGPT cannot connect or asks for a login. Check that the URL contains /api/mcp/, since the wizard page and the dashboard are not MCP addresses. Then check that the server is public in MCP Studio. A private server expects an access token, and ChatGPT has no field for one.

You changed the server's tools. Open the app's details page in settings and refresh it so ChatGPT picks up the new list.

Tools load but answers are thin. Indexing may still be running, or the question uses different words than the source. The wrong information guide walks through both.

Frequently asked questions

Can ChatGPT use MCP servers?

Yes. ChatGPT on the web connects to remote MCP servers through developer mode, on Plus, Pro, Business, Enterprise, and Education plans. Each server becomes an app you select in a conversation.

Can I connect a private MCP server to ChatGPT?

Not with an MCP Studio access token. ChatGPT connects with OAuth or with no authentication, so connect a public server. For confidential material, keep the server private and use it from Codex, Claude, or Cursor, which send the token with every request.

Is ChatGPT on the web the same as Codex in the desktop app?

No. They keep separate server lists. An app you create in ChatGPT's settings does not appear in Codex, and a server in Codex's configuration does not appear in ChatGPT on the web. Add the server to each one; the URL is the same.

Do I need to write code to build an MCP server for ChatGPT?

No. MCP Studio builds and hosts the server from a documentation site, a GitHub repository, or uploaded files. You pick the tools in a wizard, deploy, and paste the URL into ChatGPT.

Is it free to try?

Yes. The MCP Studio free tier includes 3 servers, 2 sources per server, and 50 MCP requests a month per account, which is enough to connect ChatGPT and test real questions before you decide on a plan.

Connect ChatGPT to your docs with MCP Studio

Build a server from one source, add its URL as a ChatGPT app, and ask a question you already know the answer to. The wizard takes about a minute and needs no code. Create your server in MCP Studio.

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