financetaxx402calculatorsusdc
Discover and preview 56 verified finance and tax calculators, then verify paid results through x402 payment flows.
Quick Install
Automated & IDE SetupCopy the AI prompt to install this server into Claude Code, Cursor, or another agent — or use 1-click editor setup below.
We couldn’t automatically confirm this listing starts correctly
We ran the install command below but it didn't respond within our test window — this can mean a slow first-time install rather than a real problem.
npx -y tollbooth-x402No response to initialize.
This is an experimental automated check and can have false negatives — missing environment variables, a slow cold install, etc. It doesn’t necessarily mean something’s wrong. Last checked 7d ago.
Manual Client & Custom JSON ConfigExpand JSON â–¾
Client Config & Setup
Choose your client or environment
Target File:
💡 Paste the JSON block into your client's configuration file under mcpServers, then restart the application.
Overview
Use cases
Browse available finance and tax calculators before selecting an endpoint
Preview paycheck, tax, lending, or business calculations without payment
Verify the provenance hash of a paid calculator response
Explain the x402 payment flow to an AI agent
Key features
Catalog of 56 finance and tax calculators
Free rounded calculator previews
SHA-256 response hash verification
x402 payment instructions
USDC payments over Base
Capabilities & Tool Schemas (4)
Inspect callable tools, capabilities, and parameters exposed to AI agents by Tollbooth X402.
tollbooth_catalogCallable MCP tool function
tollbooth_previewCallable MCP tool function
tollbooth_verify_hashCallable MCP tool function
tollbooth_how_to_payCallable MCP tool function
How Tollbooth X402 works
What the tollbooth-x402 MCP server does
The tollbooth-x402 MCP server connects MCP clients to a catalog of verified, pay-per-call calculators for AI agents. The catalog covers tax and payroll, crypto and DeFi, lending, real estate, retirement, and business calculations. The README describes 56 available calculators, including tools for paycheck estimates, self-employment tax, capital gains, mortgage affordability, LLC costs, debt plans, and impermanent loss.
The MCP layer itself provides discovery and verification functions. Calculator endpoints may require payment, while the MCP tools listed in the README are free to use and do not require a wallet.
How it works
An agent can first inspect the catalog to learn which endpoints exist, how much each costs, which method it uses, and what input schema it expects. It can then request a coarse, rounded preview before deciding whether a paid calculation is appropriate. After a paid response is returned, the agent can re-derive its hash with the verification tool to check that the response was not altered.
Payment follows the x402 protocol. Paid requests go directly to https://x402toll.com, use USDC on Base, and are handled by an x402-capable wallet or client. The README states that these calls do not require an account or API key. The tollbooth_how_to_pay tool explains the payment flow to an agent.
Setup and configuration
Install the tollbooth-x402 MCP server with:
An MCP client configuration can run it through npx. The README specifically gives Claude Desktop and Cursor as example clients. The server uses the default x402toll.com gateway unless TOLLBOOTH_URL is set to a different gateway.
Tools and capabilities
The tollbooth-x402 MCP server exposes four tools:
tollbooth_catalog: Lists endpoints with prices, input schemas, methods, and golden-vector evidence.tollbooth_preview: Produces a free rounded preview for supported calculator types.tollbooth_verify_hash: Recomputes a paid response's hash for provenance checking.tollbooth_how_to_pay: Describes how to pay for protected endpoints with x402.
Each calculator response is described as including a formula trace and a reproducible SHA-256 hash. The catalog's golden-vector evidence supports reviewing the available reference checks before making a paid request.
Limitations and notes
The previews are coarse and rounded, so they should not be treated as substitutes for paid results. The listed calculators are estimates only and are not financial, legal, or tax advice. Paid calls require an x402-capable wallet or client with the ability to make the required USDC payment on Base; the MCP server does not remove that payment requirement.
The calculations are intended to reflect exact 2026 data such as tax brackets, contribution limits, and state fees, but users should still validate outputs for their own circumstances. Changing TOLLBOOTH_URL points the client at another gateway, so that gateway must provide the expected compatible service.
Related MCP Servers
Adoption & maintenance
Factual signals from GitHub, npm, and our automated checks — not a rating.
Last commit
2mo ago
Most recent push to the default branch.
Install check
Inconclusive
Didn't respond in our test window — often a slow first install.
Tools exposed
4
Callable tools this server registers over MCP.
Directory activity
3 views
Config copies, upvotes, and views on AllMCPs.
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Frequently Asked Questions about Tollbooth X402
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