Claude Code[01]

MCP in Claude Code

One command. No key to paste — Claude Code asks you to approve Onto the first time it uses it.

Install

[02]

Add the server

Run this in a terminal:

claude mcp add[bash]

claude mcp add --scope user --transport http onto https://api.buildonto.dev/mcp

--scope user adds Onto for every project on this machine. Without it, Claude Code adds it to the current folder only.

Approve Onto

The first time Claude Code calls Onto, it asks you to sign in with your Onto account and approve. If it hasn't asked yet, type /mcp in Claude Code and pick onto. No account yet? The free tier is 1,000 credits a month.

Run it locally instead

[03]

The local server (@ontosdk/mcp, Node 20+) runs on your machine and uses an API key instead of a sign-in. Get a key at app.buildonto.dev/read/keys. The server exits straight away without ONTO_API_KEY, so pass it with -e:

claude mcp add --scope user onto -e ONTO_API_KEY=onto_sk_live_YOUR_KEY -- npx -y @ontosdk/mcp@latest

Claude Code saves the server itself — there's no file to edit.

Verify

[04]

Start Claude Code and ask:

What MCP tools do I have available?

You should see all six tools — read_url, read_and_score, score_url, extract_data, map_site, and batch. If they're missing, see Troubleshooting.

Try it

[05]

Useful prompts: