Receipts

Receipts are structured evidence of outcomes.

They are not logs, recommendations, or explanations. A receipt answers:

• what was attempted
• what inputs mattered
• what outcome occurred
• what evidence binds that outcome to the log or artifact

Receipt Classes

Implemented or active receipt-shaped outcomes include:

• append receipts
• denial outcomes
• replay and read evidence reports
• projection evidence reports
• snapshot and chain-walk reports
• receipt verification outcomes
• release and inspection reports emitted by tooling

Only canonize a receipt category as public when code, tests, and traceability make it real.

Verification

Verification should expose typed outcomes where callers need to distinguish failure reasons. Boolean projections may remain as ergonomic helpers over typed truth.

On the reference host, receipt.verify accepts ack-shaped append receipt fields (the same shape as a bank.commit ack) and returns { valid, outcome, reason_code }. Wire outcome is "signed", "unsigned_accepted", or "invalid". When invalid, reason_code is a stable snake-case string mapped from substrate verification errors — never debug formatting.

Verification is also available store-free: from portable inputs — the receipt’s ack fields, the covered chain metadata (coordinate, kind, previous-hash), and the verifying keys — with no store open and no filesystem. The store-free and store-side surfaces share ONE implementation, so their verdicts cannot disagree, and the store-free path is wasm32-clean.

Reports

Evidence reports are receipt-shaped artifacts for inspections and derived views. They should name inputs, output hashes, versions, and the reason for any refusal or fallback.

The reference host surfaces the substrate evidence-report family over NETBAT/1 through the domain-neutral evidence.* ops, with domain-neutral receipt kinds:

• receipt.evidence.chain_walk.v1 — evidence.chain_walk
• receipt.evidence.store_resource.v1 — evidence.store_resource
• receipt.evidence.read_walk.v1 — evidence.read_walk
• receipt.evidence.projection_run.v1 — evidence.projection_run

Each ack ships the report body as a canonical-encoding blob (report_hex) alongside its body_hash. Evidence-report identity is the content hash over the canonical body bytes, so the wire ships the exact bytes the hash covers: a consumer re-hashes report_hex and confirms it equals body_hash. A typed field-by-field mirror would re-encode and break that identity, so the blob form is the identity-preserving shape.