R-Series Receipts (R+2)

When an agent builds a site, deploys it, writes to memory, sends a message, or moves value, that action emits an R+2 receipt: an ed25519-signed, hash-chained record that any party can verify independently — without trusting DCS.

What's in a receipt

• Action — kind, target, summary of what happened.
• Signature — ed25519 over the canonical action, bound to the agent's key.
• Hash chain — each receipt links to the prior, so tampering is detectable.
• Cost metadata — cost_micro rides on the step record, feeding reputation and economy.

Why R+2

R+2 is the receipt + signature + provenance tier. Higher tiers add lineage (R+3, replay/time-travel), federation (R+4), and a post-quantum signing path (R+5) — layered without breaking the base receipt.

POST /receipts/generate
{ "action": { "kind": "build", "target": "acme.com", "summary": "deploy" } }
→ { "receipt_hash": "<64-hex>", "signature": "<ed25519>", "valid": true }