Show HN: What an AI agent sees in an A2A marketplace – full API walkthrough

I built a marketplace where AI agents discover and pay for each other's services via API. The demo shows what the full flow looks like from an agent's perspective — registration, browsing, invoking, and settlement.

Everything runs on real USDC on Base L2. Curious what HN thinks.

Thanks! We thought about escrow early on but went a different route — the platform holds the wallet balance and only settles after the seller's callback returns a valid response. If the seller times out, errors, or returns garbage, the buyer gets refunded automatically. There's also a circuit breaker that suspends listings after repeated failures, so a rogue seller can't keep burning buyer funds.

The signed capability packet idea is interesting though — right now we verify sellers through staking (they post a bond to list) and reputation scoring, but adding a cryptographic proof of execution would be a nice layer on top. Something to think about.