How to add a custom connector (MCP server) to Grok

Short answer

On grok.com, open Connectors, click New Connector, then Custom, paste the server's public address and sign in. In Grok Bot there's no address field: you ask it in a chat to add the server, approve, sign in from the card it shows, then type @ to use it. Either takes two or three minutes. Grok's docs say connectors are available to all Grok users, and Grok Bot needs one of its eligible plans.

What a custom connector is

A custom connector is an MCP server: a connector that lets the assistant use another app, through a standard called the Model Context Protocol. Grok has built-in connectors for Gmail, Google Drive, Outlook, Teams and a few more, plus a catalog with Notion, GitHub, Linear and others (Grok's connector docs). For anything else, you add the app's MCP server yourself. Grok then finds the server's tools and uses them in your chats, like a built-in connector.

This guide uses Upsy as the worked example. Upsy is one MCP server that gives Grok your Gmail, calendar, Drive, Slack, Notion, Linear and other apps, plus your memory, files and a cloud browser signed in to your sites, with limits you set for each app.

What Grok needs from the server

Grok's tunneling page says Streamable HTTP servers work through Cloudflare's quick tunnels, while older SSE servers need ngrok. Upsy uses Streamable HTTP at a public address, so none of that applies to it.

What you need

• Grok: a grok.com account. On Grok Business or Enterprise, an admin adds the custom connector first (see below).
• Grok Bot: Cursor Pro, Pro+, Ultra, Teams or Enterprise, or a linked SuperGrok, SuperGrok Plus, SuperGrok Heavy, X Premium+ or Grok Business seat (plans). On a Cursor team, the admin's plugin policy applies.
• The server's address. For Upsy, sign up free at upsy.ai and connect your apps under Apps first. The address is:

https://upsy.ai/connect

Upsy signs in with OAuth, so there's no API key to copy.

Add a custom connector on grok.com

1. Go to grok.com/connectors.
2. Click New Connector, then Custom.
3. Paste the server's address, here https://upsy.ai/connect, and add it.
4. Complete the sign-in. For Upsy, its page opens: sign in, then choose what Grok can use. Everything starts on, so untick apps Grok shouldn't have and set any you want limited to Read-only.
5. Start a new chat and ask for something the server can do.

There's a shortcut for Upsy. Under Assistants, click Add assistant, pick Grok under Which assistant? and click Copy prompt. Paste the prompt into a Grok chat and approve the card Grok shows. The prompt gives Grok the name, the address and the sign-in details, and asks it to start the sign-in.

Add a custom MCP server to Grok Bot

1. Open a chat with any Bot.
2. Ask it to add the server, and say "custom MCP server" so it doesn't install a catalog plugin with a similar name. For example: Add a custom MCP server named Upsy at https://upsy.ai/connect. Or paste Upsy's setup prompt from above.
3. Approve when Grok Bot asks to add it.
4. Click Authorize on the card it shows and finish the sign-in in your browser. If it says Waiting for authorization, use Reopen to bring the tab back (Cursor's help).
5. Type @ in the chat and pick the server, here Upsy.

The server is added for your whole account, so every Bot can use it. If a server asks for an API key, don't paste it into the chat: Grok Bot's docs say to enter secrets in its secure secret request, which masks them.

For Grok Business and Enterprise

On Business and Enterprise plans, members can only use connectors a team admin has added (connector management). The admin signs in at console.x.ai, selects the team and opens Grok Business › Connectors. Then they click + Add Connector, select Other, enter the server's address and complete any authentication. It takes the Team Read-Write permission. Members then connect their own accounts on grok.com/connectors.

Check that it works

On grok.com:

Using Upsy, what can you do for me? List the apps you can reach.

In Grok Bot, attach Upsy with @ first. Grok should list the apps you connected in Upsy and what it may do with each. In Upsy, History shows the call under the assistant that made it.

What Grok can do through Upsy

• Gmail: search, read, draft, send and organize, across up to five accounts.
• Google Calendar: see, create, change and answer events, and find free time.
• Google Drive, Docs and Sheets: search and read files, save new ones, suggest edits in Docs and update Sheets.
• Slack: read channels and threads and send messages as you. See connecting Slack to Grok.
• Apps through their own MCP servers, such as Notion, Linear, Jira, Todoist and Stripe, each with its own sign-in.
• Memory, files and a cloud browser signed in to your sites.

For each app, you give each assistant Full access, Read-only, Pick actions (only the actions you choose) or No access.

Prompts to try

• "Using Upsy, summarize my unread email from today."
• "What's on my calendar tomorrow, and where do I have an hour free?"
• "Find the Q3 planning doc in my Drive and list the open questions."
• "Read my Upsy memory and tell me what you know about my travel preferences."
• "@Upsy create a Linear issue for the login bug we discussed." (Grok Bot)

Troubleshooting

Grok rejects the address

Grok only accepts servers it can reach over the public internet. A localhost or private network address won't work. Run the server somewhere public, or use a tunnel such as ngrok or Cloudflare Tunnel, as Grok's tunneling page describes.

It worked, then stopped

A free tunnel usually gets a new address when it restarts. Remove the old connector and add the new address. The server and the tunnel also have to keep running.

Grok Bot installed a catalog plugin instead

Ask again and say "custom MCP server", with the full address.

The plugin says it's added, but the Bot can't use it

Added means installed, not signed in. Open it from Plugins and choose Authorize if it shows Needs auth or Disconnected. Then attach it with @.

"Disabled by team admin"

On a Cursor team, the team admin controls which plugins and servers members can use. Ask them to enable it. That's separate from a Google or Microsoft admin.

The server needs its own OAuth client ID

Grok Bot's add flow takes a name, an address and optional headers, with no field for a fixed client ID, so servers that require one can't sign in yet (Poster.ly's notes). Servers that register themselves, as Upsy does, aren't affected. For other errors, see Grok connectors not working.

Security and privacy

• A custom connector can do whatever its tools do, with the access you grant at sign-in. Grok's docs don't describe any review of custom servers, so only add ones you trust.
• Keep keys out of the chat. Use the server's sign-in or Grok Bot's secure secret request.
• With Upsy, Grok never receives your app passwords or tokens. It calls Upsy's tools, and Upsy calls the app, at the level you set.
• History and alerts: every action is in Upsy's History under Grok. Upsy emails you when one assistant sends 20 or more messages, deletes 50 or more items or reads 100 or more in 10 minutes.
• Turning it off: disconnect it on grok.com/connectors, or click Remove Grok on its page in Upsy. It loses access right away.

FAQ

Can Grok use MCP servers?

Yes. On grok.com, add one under Connectors › New Connector › Custom. In Grok Bot, ask in a chat to add a custom MCP server, sign in, then attach it with @.

Does Grok support local MCP servers?

Not directly. Grok needs a public address, so a server on your computer needs a tunnel. Grok Bot runs in the cloud and can't reach your laptop either.

Do custom connectors need a paid Grok plan?

Grok's docs say connectors are available to all Grok users. Some third-party guides say custom connectors need a paid plan, so if Custom doesn't appear, check your plan, or ask your admin on Business or Enterprise.

How do I remove a custom connector?

On grok.com, open Connectors, find it and click Disconnect. In Grok Bot, open Plugins, find it under Installed and remove it.

Does a connector on grok.com also work in Grok Bot?

No. Grok on grok.com and Grok Bot are separate apps, so add the server to each.