What a activity_today receipt records
A activity_today receipt is one AER-1 record (receipt schema version 0.4, hosted profile zambo-hosted-receipt/1) for one call. Read from a real activity_today 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
activity_today, version4.0.0, scopepublic. - 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 public examples below carried private deliveries, so the saved output on the public page is the delivery notice itself: the fields visibility and message. The activity detail stays behind the owner and client links.
- Output digest: output_hash, the SHA-256 digest of those canonical bytes, with the canonical byte length recorded too (633 bytes on the first example below).
- Caller and provenance: a caller type (
anonymouson the first example) and a provenance class ofEXECUTED BY ZAMBO, which states how the record was produced. - Declared side effects: the record declares its side effects,
noneon 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 activity_today receipt examples
Each example below is a real activity_today receipt. Open one and you see the saved result, when it was saved, and its digest, the same fields described above.
zambo.dev/run/fd34a3cb-bd8c-4419-a578-b59812b310b4
Saved: 2026-10-24T09:44:54.027Z
Output SHA-256 digest: sha256:1650e2bb98b2a2168bdce8376bb55d5f04355af10299d40e04181d36245365e3
Checked live on 2026-10-24: this URL returned HTTP 200 with this receipt on the page.
zambo.dev/run/651557e4-78d0-4bc1-989d-8d13ffe0ccf6
Saved: 2026-10-24T09:23:29.500Z
Output SHA-256 digest: sha256:f49772d4da324c5778f12295f810b3fefb49062ae7007936db76d9c85b4d5857
Checked live on 2026-10-24: this URL returned HTTP 200 with this receipt on the page.
zambo.dev/run/271af3ac-7d8a-440d-889d-bc28725450f0
Saved: 2026-10-23T23:26:10.456Z
Output SHA-256 digest: sha256:37f71f35b4613067dbd48e3477f4ab8033bb8b9133d51444c8683896bfb3eea3
Checked live on 2026-10-24: this URL returned HTTP 200 with this receipt on the page.
How to verify a activity_today receipt
- 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.
- Or call the API directly:
GET https://zambo.dev/api/v2/receipt/{receipt-id}/verifyreturns the record as JSON, including its output_hash and verification_status. - 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.