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How-to guidesAdd an MCP server

Add an MCP server

Give your bots the tools of a remote MCP server, found in fxbot's list or GitHub's MCP registry, or added by its address.

  1. Open Add-ons, the puzzle button at the bottom of the sidebar, and choose the MCP tab.
  2. Type in the search above the tabs. Results tagged fxbot are the project's own picks; the rest come from fxbot's copy of GitHub's MCP registry, which it refreshes every hour.
  3. Choose a result to open its page. fxbot looks at the server and shows where it runs, how it signs in, the keys it needs, and who published it.
  4. For a server that needs a key, paste it into the field the page names.
  5. Choose the Add button, which names the server. fxbot shows it under Installed.
  6. For a server that signs in with OAuth, choose Sign in and approve fxbot on the page that opens.
  7. Choose the pencil button on its row. Under Bots, keep All bots, or choose Choose and switch it on for each bot that should have it.
  8. Under Tools, allow the ones bots may call. Only the read-only tools are allowed at first.

By its address

For a server the registry doesn't list. Its docs give the address, often ending in /mcp.

  1. On the MCP tab, choose Add by address.
  2. Paste the address and choose Look. fxbot shows the server's name, and either its tools, Takes a key, or Signs in with OAuth.
  3. For a server that takes a key, paste it. It is sent as Authorization: Bearer; for another header, write it as Name: value.
  4. Choose the Add button, then follow steps 6 to 8 above.

A bot's Edit page lists the servers too, under Add-ons.

When it goes differently

  • The search doesn't find it. Tick Search everything to look in the official MCP registry as well. Nobody reviews its entries, so check who published one before you add it.
  • The page warns that the server isn't on the publisher's domain. The registry checks who published an entry, not where its server runs. Add it only if you trust that host.
  • The page says it runs on this machine. That server is a program, not a remote server, and fxbot can't add it yet.
  • The address is local or private. fxbot refuses it unless you tick Allow a local address. Tick it only for a server you run: it can then reach this machine and your private network.
  • The sign-in page doesn't come back. fxbot comes back to its own address when you use it at an HTTPS address, such as your tailnet's. Elsewhere, the page the sign-in sends you to may not load: copy its address from the browser, and paste it into fxbot.
  • The server signs in with OAuth, but you have a key. When adding by address, choose Use a key instead before adding it.

Update a server

A server added from the registry says Update available on its row when the registry has a newer version. Open it with the pencil button and choose Update to: fxbot shows what the new version changes, and moves to it only when you choose Update. A row may also say Deprecated or Removed from the registry; the server keeps working as added.

Why only read-only tools to start: see Security model.