How to Connect Grok to MCP Tools

To connect Grok to an MCP server, open grok.com/connectors, choose New Connector → Custom, enter the server URL, and complete authentication. xAI’s Connectors guide↗ (opens in a new tab) says connectors are available to all Grok users, with an extra administrator step for Business and Enterprise. MCP is a standard way for an assistant to use an outside tool; fenbs uses it to keep work available across assistants.

A successful connection has two parts: Grok can reach the server, and the account you signed in with can access the intended information. Start with a small read that you can check before asking the assistant to change anything.

What do you need before adding the connector?

• The service’s real MCP server URL, supplied by the service or the person operating it.
• A server reachable from the public internet, rather than a localhost or private-network address.
• An account with appropriate access to the service and permission to connect it.
• A small, non-sensitive record you can use to verify a read after signing in.

Use the documented web flow. The guide does not establish an equivalent native iOS or Android custom-connector setup path or a complete country-availability matrix. Also check which workspace you intend to use before testing: a successful connection should be checked in the actual setting where you plan to work.

Instructions about how the assistant should respond are a separate matter. The xAI system prompt guide covers that intent; writing an instruction is not the same as signing in and authorizing a tool.

How do you add a custom connector on the web?

1. Sign in to Grok and open grok.com/connectors.
2. Choose New Connector, then Custom.
3. Enter the MCP server URL supplied by the service.
4. Complete the required authentication. Read what access you are approving and use the intended service account.
5. Ask for one harmless read and compare the result with the original record in the service.

Follow xAI’s custom-connector instructions↗ (opens in a new tab) for the URL and authentication steps, then check the actual tools available through your connection. A saved connector does not mean every tool is appropriate for every task or that the signed-in account has unlimited access.

Choose a test whose answer you already know: the title of a sample task, for example. Ask the assistant to read that exact record. Check both the returned title and which service supplied it. A plausible answer without a clear tool result is insufficient evidence that you connected the right source.

What changes for Business and Enterprise?

An administrator must provision the connector before members can connect their own accounts. The Connector Management guide↗ (opens in a new tab) says adding or removing connectors requires Team Read-Write permission, usually held by a team administrator. A member completing personal sign-in does not replace this organization setup.

1. As an authorized administrator, sign in to console.x.ai and select the team.
2. Open Grok Business → Connectors.
3. Choose + Add Connector, then Other for a custom MCP server.
4. Enter the server URL and complete the required authentication or setup.
5. Have each member connect their own account at grok.com/connectors, then verify an appropriate read.

Record who manages the organization setup and which account performed the test. Keep credentials out of that record. If a member cannot see the connector, check provisioning and membership before assuming the MCP server is broken.

Why is a localhost or private URL rejected?

Grok’s servers must reach your MCP server over the public internet. A URL that works only on your own laptop or office network does not satisfy that requirement. The custom MCP tunneling guide↗ (opens in a new tab) explains that a tunnel can forward a public URL to a local server, while authentication remains necessary.

For a local test, both the server and its tunnel must stay running. Temporary tunnel URLs often change after a restart, so a connector can point at an obsolete address even though the local service still works. Check the current public URL before repeatedly signing in or changing permissions.

The guide also warns that Cloudflare quick tunnels do not support SSE, an event-stream connection format. Streamable HTTP works with those tunnels; an SSE server needs another suitable tunnel option. Follow the server operator’s transport instructions instead of assuming every public URL supports the same connection.

How do you separate access problems from connection problems?

Check the failure in order: can Grok reach the URL, did authentication finish, and can that account read the intended record? Those are separate questions. A network failure does not become a permission failure merely because the error appeared after a sign-in attempt.

• Wrong or stale URL: verify the endpoint with the service operator, especially after restarting a tunnel.
• Incomplete sign-in: finish the service’s authentication flow with the intended account.
• Wrong account or workspace: compare the test record with what that account can access directly.
• Unexpected write behavior: stop and review the service permissions before testing more changes.

After a read succeeds, test a change only on a disposable record you control and are authorized to edit. Read it back to confirm the result. Save the verified access and remaining limits in the fenbs work record, so the next session can distinguish a tested connection from an assumed one.

Is the developer API configured the same way?

No. xAI separately documents remote MCP tools for its native SDK, OpenAI-compatible Responses API, and Speech-to-Speech API. Its Remote MCP Tools reference↗ (opens in a new tab) supports Streamable HTTP and SSE, and says the Responses API require_approval and connector_id parameters are unsupported. Do not transpose those API parameters onto the consumer connector form.

Choose the web connector instructions when you want tools inside an ordinary Grok conversation. Choose the developer reference when you are writing an application. For organizing source files instead, use the Grok Projects guide; for cross-chat recall, use the Grok memory guide.

How to keep connected work with fenbs

Keep the checked setup and useful work so you can carry on from exactly where you left off, on any device and in any other AI. Another assistant should be able to see what you tested and what still needs attention.

1. Create a free account.
2. Connect Grok to fenbs. Choose what it is allowed to do.
3. Ask Grok to read the saved work. Check a small result before relying on it.
4. Save the connection checks, completed work, and next step. Leave passwords and tokens out.

fenbs does not host your custom MCP server or replace its authentication. You do not need it merely to test a one-off connection. For broader tool choice, see Grok versus ChatGPT and Claude versus Grok; the connect AI hub covers other connection workflows.