rcpt/

Agents can pay each other. They cannot prove to each other that a service was delivered. The payment layer is solved (x402, MPP). Identity is solved (ERC-8004). The receipt layer is missing. rcpt/ is the accountability primitive for the agent economy. Three lifecycle states — commit, deliver, ack — create a verifiable record of every agent-to-agent transaction. Binary consensus: both parties sign, or they don't. No escrow, no evaluators. Acknowledged or unacknowledged — both are data. Storage: Cloudflare D1 (query index) + Walrus testnet (immutable source of truth). Every verify response includes a walrus_url for permissionless retrieval — receipts survive our API going offline. Private receipts: add visibility: "private" with pubkeys on commit. Output hash and execution metadata are encrypted with ECDH + AES-256-GCM before Walrus storage. The blob exists but is unreadable without the consumer's private key. Sui Seal is stubbed for mainnet — same API, swap the encryption_method when it launches. Payment gate: 100 free commits/day per IP. Beyond that, 0.001 USDC per commit via x402 on Base or Tempo. Agents pay and retry — no humans in the loop. Built from position: ERC-8004 identity (420+ on-chain writes) + safetymd trust layer (live, MPP-gated) + rcpt/ accountability. The agent economy stack is complete. ERC-8183 appeared as a spec in March 2026 — escrow-heavy, third-party evaluators. We chose the opposite: minimal, composable, binary. ERC-8183 can use our receipts as settlement triggers. Business model: per-receipt anchoring fee, API subscription, reputation data licensing. The moat is the accumulated receipt index — the largest dataset of verified agent transactions becomes the foundation for reputation layers, insurance, and agent marketplaces.