MCP in Windsurf

Add Onto to Windsurf's Cascade so the agent can call read_url, score_url, and read_and_score while you code.

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Windsurf uses the standard mcpServers schema, identical to Claude Desktop and Cursor — so if you have an existing block from those, the same JSON works here.

Install steps

Get an API key

Grab a key from app.buildonto.dev/read/keys. Free tier: 1,000 requests / month.

Open Cascade settings

In Windsurf: Settings → Cascade → MCP Servers. Click "Add server" (or "Edit raw config" if you prefer the JSON path).

Add the Onto server

Paste the standard block:

json

{
  "mcpServers": {
    "onto": {
      "command": "npx",
      "args": ["-y", "@ontosdk/mcp@latest"],
      "env": {
        "ONTO_API_KEY": "onto_sk_live_your_key_here"
      }
    }
  }
}

Refresh Cascade

Cascade picks up the change after saving. If tools don't appear, restart Windsurf — MCP server detection runs once per process.

Via the file

If you'd rather edit the config file directly, Windsurf stores Cascade's MCP config under your user profile:

bash

~/.codeium/windsurf/mcp_config.json

The schema inside is identical to the block above — same mcpServers wrapper. Save the file, then refresh Cascade or restart Windsurf.

Verify

Open Cascade chat and check the available tools list — onto should appear with six tools connected.

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Try it: "Use the onto MCP server to read https://stripe.com and give me the AIO score."