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.