AGENT CONTRACT PROOF
Verify a paid agent before another agent trusts, integrates, or repeatedly pays it.
https://agent-contract-proof.mattskowronis.workers.dev/v1/verifyWhy an agent buys it
A SMALL CHECK BEFORE A COSTLY MISTAKE
Compares an agent’s public Agent Card or OpenAPI contract with its live x402 payment challenge. It returns deterministic proof of the advertised route, method, price, network, wallet, asset, and schema coverage—and makes silent contract changes visible with a stable hash.
- 01
Preflight a paid tool before sending it money or customer work.
- 02
Detect a changed price, payment wallet, network, route, or schema before an automated integration breaks.
- 03
Monitor a dependency by comparing its current contract hash with the hash saved on the previous run.
- 04
Fail closed with explicit mismatch, unreachable, or insufficient-evidence states instead of guessing.
What comes back
STRUCTURED FOR THE NEXT DECISION
A fixed JSON shape containing verdict, normalized declared and observed contracts, individual checks, mismatches, evidence URLs, checked_at, contract_hash, and service_version.
- Advertised HTTP method and paid path
- Live x402 version and exact payment scheme
- Price, network, receiving wallet, and payment asset
- Declared input and output schemas
- Stable SHA-256 contract hash for change detection
- Evidence URLs and field-by-field pass, fail, or unknown results
Minimal request
ONE CALL. ONE DETERMINISTIC RESULT.
First request the endpoint normally. Its HTTP 402 response supplies the exact price and payment instructions. Retry with a valid x402 payment signature.
{
"url": "https://source-claim-proof.mattskowronis.workers.dev",
"method": "POST"
}Built for monitoring
THE HASH MAKES CHANGE VISIBLE
Save the returned contract_hash. Pass it back later as expected_hash. If the public contract changed, the response says so without requiring this service to retain your data.
Verified distribution
WHERE OTHER AGENTS CAN FIND IT
Each status below links to the independent registry or its public record.
Published remote MCP server · version 1.0.0
Domain-approved x402 listing · live 402 challenge verified
Public Agent Card and A2A endpoint indexed
One tool discovered from the public x402 manifest
Validated metadata · successful Base settlement · indexed resource
Machine discovery
EVERY PUBLIC INTERFACE
Use the native interface your agent already understands.
https://agent-contract-proof.mattskowronis.workers.dev/v1/verifyMCP streamable HTTPhttps://agent-contract-proof.mattskowronis.workers.dev/mcpA2A JSON-RPChttps://agent-contract-proof.mattskowronis.workers.dev/a2aOpenAPI 3.1https://agent-contract-proof.mattskowronis.workers.dev/openapi.jsonA2A Agent Cardhttps://agent-contract-proof.mattskowronis.workers.dev/.well-known/agent-card.jsonHealthhttps://agent-contract-proof.mattskowronis.workers.dev/health