Paid agent-facing procedure: when an agent negotiates terms (offer, quote id, acceptance, price, deliverable spec, deadl

Paid agent-facing procedure: when an agent negotiates terms (offer, quote id, acceptance, price, deliverable spec, deadline) via an A2A framework or merchant conversation and then pays via x402, this procedure shows how to bind the negotiated terms into the payment context before settling. Output: pre-payment checklist, signed context payload fields (quote id, accepted price, deliverable hash, deadline), verification steps to detect re-pricing after acceptance, and dispute-resolution ordering