solvegate-mcp

An MCP server that lets an agent deal with Cloudflare Turnstile: check whether a page has one, and clear it when it does.

Three tools. One of them needs no account.

Install

npx solvegate-mcp

Claude Desktop / any MCP client, in your config:

{
  "mcpServers": {
    "solvegate": {
      "command": "npx",
      "args": ["-y", "solvegate-mcp"],
      "env": { "SOLVEGATE_API_KEY": "sk_test_…" }
    }
  }
}

Leave SOLVEGATE_API_KEY out and inspect_page still works. That is deliberate: you should be able to see what the server does before deciding whether to sign up for anything.

Get a key at solvegate.io. A free sk_test_ sandbox key needs no card and returns a deterministic token instantly — right for wiring this up, and it never clears a real gate.

Why inspect_page exists

The commonest wrong turn with a solver is calling it when you should have looked first. Three cases account for most of it:

• The page carries reCAPTCHA or hCaptcha, not Turnstile. Those are different products from different vendors. This server does not solve them, and neither does SolveGate — inspect_page says so by name instead of letting you find out from a 422.
• It is a WAF challenge, not a widget. A full-page Cloudflare interstitial has no data-sitekey, because the challenge belongs to a zone rule rather than to a widget you embed. There is nothing to read off the page, and the gate is waf rather than turnstile.
• The sitekey is rendered from script after load. Then it is not in the served HTML at all, and the tool says that rather than guessing.

Inspecting is free, takes about a second, and is quite often the whole answer.

What it will not tell you

The widget mode. Managed, non-interactive and invisible are stored on the widget inside the Cloudflare account that owns the sitekey. The page carries only the key, so no tool can read the mode off the source — including this one, and including anything that claims otherwise.

It does not matter for solving: all three modes resolve to the same request. A sitekey, a page URL, and a token back.

The one exception is Cloudflare's five documented dummy sitekeys, whose widget type Cloudflare publishes itself. inspect_page reports those, and finding one on a page tells you something useful — you are looking at a staging build rather than production.

Configuration

The key is read from the environment and is never a tool argument — a tool argument is model-visible and ends up in transcripts.

Notes on behaviour

Solving is async underneath. solve_turnstile creates the solve with async: true and polls it, rather than holding a connection open for the whole attempt. An agent's tool call has a timeout it does not control, and a synchronous solve makes a slow gate look like a dead tool. It also means a timeout here leaves you a solve id: the error names it, and get_solve will pick it up rather than losing a solve that was already billed.

Errors are results, not exceptions. Every failure comes back as an isError result carrying SolveGate's own error.code — balance_empty, unknown_sitekey, rate_limited, forbidden_target. A model can act on those. It can do nothing useful with a stack trace.

Tokens are single-use and short-lived. expiresAt is Unix seconds; past it, Cloudflare stops accepting the token and the solve record is just a record. Request a token at the moment you submit it.

Check mode before trusting a token. An sk_test_ key returns mode: "sandbox", and a sandbox token will not clear a real gate. The field exists so a test key in a production config fails loudly rather than quietly.

Acceptable use

Solve only against properties you own or are authorised to test. This exists for end-to-end tests that keep failing on a challenge, CI against your own staging, and synthetic monitoring of your own production. The acceptable use policy is the binding version, and targets on the denylist return 403 forbidden_target regardless of what any agent asks for.

Development

npm install
npm run build
npm test          # spawns the built server and speaks MCP to it
OFFLINE=1 npm test  # skips the two tests that reach the network

The tests drive a real stdio transport rather than calling the tool callbacks directly. That is on purpose: a schema the SDK rejects at registration, or a stray write to stdout — which corrupts the transport, since stdout is the transport — only shows up when something actually speaks the protocol to it.

Links

• SolveGate API reference
• OpenAPI spec
• Turnstile checker — the same inspection this server exposes, in a browser
• Turnstile error index

MIT.