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io.github.SolomonisBlack/tollbooth-x402

Official registry Finance and payments

Discover, quote, verify & self-check 56 x402 pay-per-call finance/tax calculators for AI agents.

Source code Website Documentation

What can you do with io.github.SolomonisBlack/tollbooth-x402?

  • 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.

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package tollbooth-x402
Claude Code 
claude mcp add tollbooth-x402 -- npx -y tollbooth-x402@0.6.0
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "tollbooth-x402": {
            "command": "npx",
            "args": [
                "-y",
                "tollbooth-x402@0.6.0"
            ]
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. tollbooth-x402
  2. Install
  3. Tools (all free, no wallet)
  4. Categories

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.

Frequently asked questions

What is io.github.SolomonisBlack/tollbooth-x402?

Discover, quote, verify & self-check 56 x402 pay-per-call finance/tax calculators for AI agents.

How do I install io.github.SolomonisBlack/tollbooth-x402?

It runs on your machine. In Claude Code: claude mcp add tollbooth-x402 -- npx -y tollbooth-x402@0.6.0. For other clients, paste the JSON configuration from this page into their MCP settings.

Does io.github.SolomonisBlack/tollbooth-x402 need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is io.github.SolomonisBlack/tollbooth-x402 open source?

Its code is public on GitHub, but the repository does not declare a standard license.

Who maintains io.github.SolomonisBlack/tollbooth-x402?

It is published by SolomonisBlack. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.