x402-market MCP server

Read from the package source without running it. The installed server may list more.

• call_api_paid

  [Low-level / debugging only.] Use this tool when you have already broadcast a USDC payment yourself and just need the marketplace to verify+forward. Returns the upstream API response. For end-to-end pay-then-call in one step, use pay_and_call instead.

• call_api_unpaid

  [Low-level / debugging only.] Use this tool when you want to inspect a listing's exact 402 challenge (price, recipient, network) without spending USDC. Returns the raw 402 body. For production use, prefer pay_and_call --this tool does NOT invoke the upstream API.

• claim_refundwrite action

  Use this tool when a previously paid call failed (upstream returned non-2xx or took >30s) and the user asks for a refund. Auto-judge approves on status='failed' or latency_ms>30000, rejects otherwise. Returns the API's HTTP status + JSON response (judgment + refund_status). Approved refunds broadcast on the next payout-cron run (Mon 00:00 UTC); rejected refunds are final. Signs the request with MC

• get_listing

  Use this tool when you already have a listing slug and need its full schema before invoking it (request_schema, response_schema, example_request, example_response, when_to_use, output_format_description). Returns one listing as JSON. Prefer this over list_catalog when the slug is known --it is one row, not the entire catalog.

• list_catalog

  Use this tool when the user asks what APIs are available, or you need to discover paid APIs to satisfy a task (e.g. 'find a sports prediction API'). Returns a JSON array of active marketplace listings with seller_slug, listing slug, name, description, price_usdc, category, use_cases, and tags --enough metadata to pick which listing to call without a second round-trip.

• pay_and_callwrite action

  Use this tool when the user wants to actually invoke a paid API and receive its response (the normal case). End-to-end: GET the 402 price, send USDC on Base from the configured buyer wallet, retry with X-Payment, and return the upstream JSON. Returns { status, data, tx_hash, price_paid_usdc, pay_to } as text. The agent never has to handle a wallet, chain id, or payment header itself --this tool is

• Code scan2 source files scanned25/25
• –Live reliabilityno gateway calls yet and no remote to proben/a
• –Tool poisoningtools not inspected (local package is not executed); not countedn/a
• Auth qualitystatic API keys via environment variables6/15
• Maintenancerepository not readable: repo not found3/15
• Maintainer identityno repository or website to verify2/10

Safety score

55/100

higher than 10% of 48,255 servers

Tools

6

the typical server has 7

Tools that change things

33%

typical: 0%. Fewer write tools means less an agent can break

Downloads a week

37

more than 28% of 12,191 servers with a package

x402-market: common questions

Is x402-market MCP server safe?

With care: it is graded C, so read the findings first (55/100). Read the x402-market safety report

How do I install x402-market?

It runs on your machine. Copy the Claude Code, Cursor, VS Code or Claude Desktop config from the install section.

Does x402-market need an API key?

Yes. The registry entry asks for MCP_BUYER_PRIVATE_KEY.

Is x402-market maintained?

The latest release is v0.2.0-alpha.1.

How does x402-market compare with other MCP servers?

safety score 55/100 (higher than 10% of 48,255 servers); tools 6 (the typical server has 7); tools that change things 33% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.