Connect ChatGPT to your company knowledge

The first time ChatGPT answers a work question using your company's actual product names, in the house tone, respecting a rule nobody typed into the chat, something shifts. I've watched it happen across our own team and in demos, and the reaction is always the same: the person stops treating ChatGPT as a clever stranger who needs the full backstory every morning.

This guide gets you there. Company Brain is a shared, human reviewed source of company facts that connects to ChatGPT through MCP. Once connected, every chat can draw on your products, tone, and rules from one governed place, and nobody on the team pastes the same background into ChatGPT again. The ChatGPT side of these steps works for any MCP connection; I'll use Company Brain because that's what we make.

A dated honesty note before we start: these steps match ChatGPT as of October 2026. Settings screens move. If a menu has drifted by the time you read this, the shape of the process holds, and our setup guide inside the product stays current. And if you're wondering what MCP even is, we wrote a plain language explanation of MCP that takes five minutes.

Before you start

This tutorial has one honest gate that the Claude Desktop version of this guide does not have: Developer Mode. Custom MCP connections in ChatGPT require Developer Mode, and Developer Mode is available on the Plus, Pro, Business, Enterprise, and Edu plans. It is not available on Free. If your team is on ChatGPT Free, you cannot add custom plugins, so bookmark this for the day that changes.

One more thing if you work in a ChatGPT workspace on a Business, Enterprise, or Edu plan: an admin has to allow Developer Mode first, under Workspace settings, then Permissions & roles. Send your admin this paragraph.

On the Company Brain side you need an account, where the free plan is fine and stays free, and your first facts written in, because connecting an empty source produces a very polite nothing. Writing the facts is the real work. This part is plumbing.

Step one: turn on Developer Mode

In ChatGPT, open Settings, then Security and login, and turn on Developer Mode. That's the whole step. Developer Mode is what lets you add an MCP server of your own choosing, which is exactly what a Company Brain connection is.

Step two: copy your company's address

Sign in to Company Brain and open the connection page. You'll find one web address for your company, the MCP endpoint. Copy it. That address is the socket everything plugs into, one per company, the same for every teammate. Your company's key is part of the address, so treat it like a password and share it the way you'd share one.

Step three: add the plugin in ChatGPT

Custom MCP servers show up in ChatGPT as plugins, and adding one is a single dialog.

1. In the left sidebar, click Plugins, or go straight to chatgpt.com/plugins.
2. Click the + button to open the New Plugin dialog.
3. Name it Company Brain, or anything you'll recognize later.
4. Choose Server URL as the connection type.
5. Paste the address from step two.
6. Leave Authentication on No Auth.
7. Tick "I understand and want to continue", click Create, then confirm.

The No Auth setting deserves a sentence, because it looks alarming on first read. There is no separate sign in step anywhere in this process. The key inside the connection URL is what authorizes the connection, which is the same reason the URL needs the same care as a password. When the connection succeeds, ChatGPT lists the Company Brain tools, and that list is your confirmation that everything worked.

Step four: enable it in a conversation

Adding the plugin makes it available. Using it takes one more click: in a conversation, enable the Company Brain plugin. Once it's enabled, ChatGPT can call the tools whenever a question touches company knowledge, and you can talk normally from there.

Test it like you mean it

Don't test with "what do you know about my company". Test with real work, because real work is where the difference shows.

Ask for something you'd otherwise have needed to brief: "Draft a short reply to a customer asking about volume pricing." "Write the product description for the site, in our tone." Watch for the product name spelled right, the tone held, the rules respected. If something comes back wrong, that's useful too. It usually means a fact is missing or fuzzy, and now you know exactly which one to fix in Company Brain.

If it refuses to connect

Five checks resolve nearly every stuck setup. First, confirm Developer Mode is actually on under Settings, then Security and login; it's easy to skim past. Second, in the New Plugin dialog, check that the connection type says Server URL; if it says Tunnel, switch it. Third, check that Authentication is set to No Auth. Fourth, remember that Free plans cannot add custom plugins, so check which plan the account is on. Fifth, in a workspace, an admin has to allow Developer Mode first, under Workspace settings, then Permissions & roles, so confirm that step actually happened.

Hand it to the team

Every teammate repeats steps one, three, and four on their own account with the same address, a few minutes each. From then on, everyone's ChatGPT works from the same reviewed facts, and when the curator updates a fact, the next conversation everywhere reflects it. No document to circulate, no version 4 to chase.

If part of your team lives in Claude, the same address works there too, and we wrote the same walk through for Claude Desktop. One source, every assistant, which is the point of doing this over MCP in the first place. For the fuller picture of what the connection can do day to day, see how Company Brain works with ChatGPT.

The connection outlives the setup. Facts change, people join, and the plumbing sits there doing its job, which is the highest compliment plumbing can get.

Go collect your moment.