All servers · Agent payments (x402) · Payments & accounting · APIs & integrations

Surface Contract: platform API behavior and x402 pre-payment checks

dev.workers.penny-mcamp.penny-surface-contract/surface-contract · v2026.10.22

Measured by MCP Station

Description written by the publisher, not verified

Surface contracts: API behavior evidence, x402 pre-payment check, MCP server preflight

Connect

claude mcp add --transport http surface-contract https://penny-surface-contract.penny-mcamp.workers.dev/mcp

{
  "mcpServers": {
    "surface-contract": {
      "url": "https://penny-surface-contract.penny-mcamp.workers.dev/mcp"
    }
  }
}

Tools as reported by the server

• list_surface_contracts
  List the platform surface contracts published in Penny's free registry, with claim counts.
• get_surface_contract
  Get the machine-readable surface contract for a platform host (read/write semantics, pending states, rate limits, limits, idempotency, pagination completeness, data portability), each claim carrying its evidence and its verification status.
• verify_surface
  Run the anonymous conformance checks for a contract now and return verified / failed / unknown / manual / unsupported per claim.
• contribute_discrepancy
  Report a platform behaviour that contradicts a published claim, or a new claim, with evidence. One-line call: POST /v1/contribute with {contractId, kind, statement, evidence[], reporter, observedAt}. Stored as pending; a published contract is never changed without independent verification. A contrac
• get_integration_recipe
  Get a plain-text integration recipe for a platform: the order of operations to use it, and a guard clause for every behaviour we measured going wrong, each naming the contract claim behind it. Derived from the contract, so it cannot drift from it.
• preflight_mcp_server
  Run the anonymous MCP handshake against ANY https MCP endpoint you name, right now, and get back a verdict (open / refused / unreachable / initialize-transport-error), the shape of any refusal body, whether the server is stateful (sets Mcp-Session-Id), how many tools tools/list returns, and the guar
• prepay_check
  Check an x402 route BEFORE you pay it. GET /v1/prepay?url=<the route> makes ONE unpaid GET with no payment header and no credential, and returns one row: the measured HTTP status, the parsed x402 v2 challenge (scheme / network / asset / amount / payTo), whether that challenge is schema-valid exact-o

Website · JSON · Text for agents · Registry updated 2026-10-22