Tollbooth X402 MCP Server

tollbooth-x402

Free MCP server for x402toll.com — a toll plaza of verified, pay-per-call calculators for AI agents. Discover the catalog, run free coarse previews, verify any paid response's provenance hash, and learn how to pay. The paid endpoints charge a few cents of USDC per call over the x402 protocol on Base — no account, no API key.

Why agents pay: the answers depend on exact 2026 data (tax brackets, contribution limits, state fees) a model can't reliably know, every answer is checked against hand-verified reference values, and each ships with a formula trace and a reproducible SHA-256 hash.

Install

npx -y tollbooth-x402

Add to an MCP client (e.g. Claude Desktop / Cursor):

{
  "mcpServers": {
    "tollbooth": { "command": "npx", "args": ["-y", "tollbooth-x402"] }
  }
}

Tools (all free, no wallet)

• tollbooth_catalog — every endpoint with prices, input schemas, methods, and golden-vector evidence.
• tollbooth_preview — a free rounded preview of a tool (paycheck, self-employment tax, capital gains, mortgage affordability, LLC cost, debt plan, impermanent loss).
• tollbooth_verify_hash — re-derive a paid response's hash to confirm it wasn't altered.
• tollbooth_how_to_pay — the x402 payment flow for the paid endpoints.

Paid calls are made directly against https://x402toll.com by an x402-capable wallet/client. Set TOLLBOOTH_URL to point at a different gateway.

Categories

Tax & payroll · Crypto & DeFi · Lending · Real estate · Retirement · Business.

MIT licensed. Estimates only — not financial, legal, or tax advice.