tollbooth-x402 MCP Server
This MCP server provides a catalog of finance/tax calculators designed for AI agents, including discovery, free coarse previews, and verification. It supports running calculators and verifying the provenance hash of any paid response, using x402toll.com’s pay-per-call model.
🛠️ Key Features
- Discover a catalog of 56 x402 pay-per-call finance/tax calculators
- Run free coarse previews
- Verify any paid response’s provenance hash
- Explain how to pay for calculator calls
- Identify calculators under x402 on Base using USDC
🚀 Use Cases
- Generating finance/tax answers where results depend on exact 2026 data
- Using calculators for tax brackets, contribution limits, and state fees
- Ensuring agent outputs are checked against hand-verified reference values
⚡ Developer Benefits
- No account and no API key required
- Paid endpoints charge a few cents of USDC per call over x402 on Base
- Provenance hash verification for paid responses
- Calculator availability is part of a searchable catalog
⚠️ Limitations
- Focused on finance/tax calculators and 2026-specific data
- Paid calls are described as few cents per call, implying usage costs