MCP serverSet up your client
API reference llms.txt
Docs›MCP Server›Set up your client
Set up your client[01]

Set up your client

Pick your client, install, ask it to read a page. Most clients only need the URL and a sign-in — no key.

Install and check

[02]

  1. Install in your client

    URL and one-command clients sign in with your Onto account. Config-file clients run the local server, which needs your key in ONTO_API_KEY and won't start without it.

    Install in
    One command
    $ claude mcp add --scope user --transport http onto https://api.buildonto.dev/mcp
    Docs →
    1. Run it in a terminal. Claude Code asks you to approve Onto on first use.
    2. Then ask Claude Code to “read example.com with onto”.

  2. Restart it, then ask

    In a new chat:

    Use Onto to read https://stripe.com/pricing and list the plan names.
  3. It works when

    The client shows a call to read_url and answers from the page — instead of fetching it itself.

    It didn’t work

    Nothing happens? A config file in the wrong place is ignored without an error. Check the path shown in step 1, save, and restart the client.

    The server exits straight away? The local server needs ONTO_API_KEY — put your onto_sk_ key in the config's env.

    Signed in, but calls fail? Check your plan has credits left on the Rate limits page — tool calls draw on the same balance as the API.

Any other client

[03]

Anything that speaks MCP works. If it takes a server URL, give it https://api.buildonto.dev/mcp and sign in when asked. If it runs a command, run npx -y @ontosdk/mcp@latest with ONTO_API_KEY set.