What a leadsignal receipt records
A leadsignal receipt is one AER-1 record (receipt schema version 0.4, hosted profile zambo-hosted-receipt/1) for one call. Read from a real leadsignal 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
leadsignal, 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 saved output carries status, executed, the leads list, trade, city, quota_tier and the quota fields free_limit and leadsignal_quota.
- Output digest: output_hash, the SHA-256 digest of those canonical bytes, with the canonical byte length recorded too (1105 bytes on the first example below).
- Caller and provenance: a caller type (
sessionon 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 leadsignal receipt examples
Each example below is a real leadsignal receipt. Open one and you see the saved result, when it was saved, and its digest, the same fields described above.
zambo.dev/run/3afab5e4-ac50-45a5-ab0a-a88ab25797bd
Saved: 2026-10-24T18:19:33.599Z
Output SHA-256 digest: sha256:30fd2eade6f77c4bb1fc23d7e92ccec6fbd3bd6de3f173da6e8ddca0018f44fd
Checked live on 2026-10-24: this URL returned HTTP 200 with this receipt on the page.
zambo.dev/run/60bef28f-8641-40fd-a6a4-2719fd1bf31b
Saved: 2026-10-24T18:19:08.697Z
Output SHA-256 digest: sha256:5c2760ee5d3f9646a876832405453a5d12f03ed8c7b2b95f61e880835c18cfbc
Checked live on 2026-10-24: this URL returned HTTP 200 with this receipt on the page.
zambo.dev/run/5ef7b22c-3175-47da-b892-0b35a8c41aee
Saved: 2026-10-24T18:09:33.623Z
Output SHA-256 digest: sha256:a20bc42d546f97eb7c34a4a9679f2d1b1f8786a4825cc1f658d021cec4f429ae
Checked live on 2026-10-24: this URL returned HTTP 200 with this receipt on the page.
How to verify a leadsignal 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.