Receipt for write

What a write receipt records

A write receipt is one AER-1 record (receipt schema version 0.4, hosted profile zambo-hosted-receipt/1) for one call. Read from a real write payload, it records:

• Receipt id: a full UUID. The id is the address of the record: the human page is https://zambo.dev/run/ followed by the id.
• Tool: name write, version 4.0.0, scope public.
• Timestamps: the record creation time, and inside the step list a started_at and a completed_at for the call itself.
• Step status: one step per call, with the tool name and its status. On the first example below the step status is success.
• The saved output: the exact output object the call returned, kept as canonical bytes. The saved output is a single field, text, holding the produced writing. The digest on the receipt is computed over the record that contains that text, so a later reader can check the wording they were shown is the wording that was saved.
• Output digest: output_hash, the SHA-256 digest of those canonical bytes, with the canonical byte length recorded too (1122 bytes on the first example below).
• Caller and provenance: a caller type (session on the first example) and a provenance class of EXECUTED BY ZAMBO, which states how the record was produced.
• Declared side effects: the record declares its side effects, none on the first example.
• Verification status: the API carries a verification_status field for the record. On the first example below, the verify API reported verification_status commitment_matches, its wording for a record whose digest still matches the saved bytes.

Live write receipt examples

Each example below is a real write receipt. Open one and you see the saved result, when it was saved, and its digest, the same fields described above.

How to verify a write receipt

1. Open zambo.dev/verify/ and paste the receipt link or the receipt id. The checker recomputes the SHA-256 digest over the saved bytes and reports whether the record still matches.
2. Or call the API directly: GET https://zambo.dev/api/v2/receipt/{receipt-id}/verify returns the record as JSON, including its output_hash and verification_status.
3. The format is AER-1, an open IETF Internet-Draft: draft-zambo-aer1-26. Anyone can implement the check; it does not need a Zambo account.

Verification answers one question: is this the record that was saved, byte for byte? It does not answer whether the result inside was right.

Get receipts for your own calls

Add Zambo to your AI once, at zambo.dev/add/, and every tool call after that files a receipt like the ones above. Every account starts with 20 free calls per day, and free calls file receipts too. The background is at AI agent receipts, and more worked examples are indexed at receipt examples by tool.