a2a-proof: black-box behavioral contracts for deployed A2A agents

[aspix2k]

a2a-proof runs repeatable black-box checks against a deployed A2A agent. It reads the Agent Card, sends real requests, and fails CI when observable behavior drifts.

It complements protocol tooling: TCK covers conformance, ITK covers SDK interoperability, and Inspector or workbenches help with interactive debugging. a2a-proof keeps application behavior under versioned contracts.

uvx a2a-proof demo
uvx a2a-proof demo --fail

The demo runs locally and needs no API key. Contracts can assert text, structured data, files, task lifecycle, latency across repeated trials, and signed AP2 mandate/receipt flows. A GitHub Action runs the same contracts in CI.

I’d value feedback from teams running A2A agents: which deployed behaviors are hardest to keep stable, and where does the contract or reporting UX get in the way?