You paid for AI work. Did you get a zambo receipt?

The one line to send before work starts

Put this in the brief or the agreement, before anyone runs anything: "Delivery includes the receipt links for the AI work behind the deliverable, and I check them before payment is released." That line costs nothing and changes everything downstream. A freelancer who works with a record hears a normal professional request. A freelancer who cannot produce a record has to say so up front, while you can still choose someone else, renegotiate, or hold part of the payment against delivery of the record.

Why before, not after? Because a receipt is fixed while the work runs. It cannot be created honestly afterward from a chat export and a memory. Asking after the job ends gets you a summary, a screenshot, or an argument. Asking before the job starts gets you the record.

Exactly what to ask for at delivery

1. The /run/ link for each AI call behind the deliverable, or the single handover link that gathers the whole job in order. The link looks like zambo.dev/run/ followed by the receipt id.
2. The saved result behind each link, readable on the receipt page itself, so you compare the record with the deliverable in front of you, not with a description of it.
3. An acceptance step you control: a handover you can accept or flag step by step, so your yes, your no, and your "fix this one step" are recorded against the work, with the date.

What does not count: screenshots of a chat, a pasted transcript, a dashboard image, or a confident summary. The person sending each of those controls it completely and can edit it without leaving a mark. The receipt link is the first item on the list precisely because the sender cannot edit what it points to after the fact: if the saved result changed, the check stops matching.

How to check a receipt in 30 seconds

1. Open the /run/ link. Read the tool name, the run time, and the saved result.
2. Paste the link into zambo.dev/verify. Read the outcome. Verified means the saved result recomputes exactly as it was saved.
3. Compare. Put the saved result next to the deliverable you were handed. A match means this step is the work that ran, unchanged since. A difference means you ask about the difference before you pay, not after.

Three outcomes, three moves. A receipt that verifies and matches: pay for that step with a clear head. A receipt that fails the check: stop, because the record changed after the work ran. No receipt at all: the step is a claim, and claims get inspected by hand, discounted, or redone. Check the two or three steps the money actually turns on, and sample the rest. That is enough: a freelancer who knows you check the load-bearing steps keeps the whole job honest.

You already paid and got no proof

This is the "paid for AI work, no proof" position. Work it in order. Ask in writing for the job record: receipt links if the work ran through Zambo, since those still check today exactly as they did on the day. If the work ran elsewhere with no record, switch from verifying to inspecting: open every deliverable, test it against the brief, and write down which parts you could confirm and which you could not. Pay in full for what you confirmed. For what you could not confirm, you are negotiating, and your strongest sentence is a factual one: "There is no record of this step, so I cannot check it." Then fix the next job with the one line above, so you are never in this position twice with the same hire.

The payer's own toolkit: the $0.99 Day Pass

Checking other people's receipts is free and needs no account. The $0.99 Day Pass solves the payer's side of the problem: for 24 hours, every call you run through Zambo at zambo.dev/mcp leaves its own verifiable receipt, so you can re-run a doubtful step yourself, keep your own record of what you paid for and what you checked, and hand the next freelancer a worked example of the record you expect back. Zambo is the verifiable work layer for AI: 153 tools behind one MCP endpoint, 35 on the default surface. Ongoing, the Zambo Pass is $29 for 30 days, one payment, or $290 for 365 days; the $ZAMBO-holder Pass is $19 for 30 days. Humans pay by PayPal or card through PayPal; agents pay USDC on Base through x402. The receipt format is AER-1, published as IETF Internet-Draft draft-zambo-aer1-26, so the record your freelancer hands you can be checked by anyone, on any tool that reads the format.

What a receipt does and does not prove

What it proves. A verifiable receipt proves the saved result was not changed since it was saved. It also fixes the record around that result: the tool that ran, the time the call ran, and the recorded inputs. Anyone holding the receipt link can recompute the check, with no account and no help from the person who ran the work.

What it does not prove. It does not prove the result was right: a source can be the wrong source, a draft can miss the brief, and code can run exactly as recorded and still do the wrong thing. It does not prove the freelancer chose the right tool, and it says nothing about work that ran outside the recorded calls. Correctness is your judgment, made by reading the saved result the receipt protects. The receipt makes that judgment possible on a record you know is intact; it never makes the judgment for you.

The gap case. A step with no receipt is not a step that failed the check. It is a step that cannot be checked at all, and it should be priced, approved, and trusted accordingly: as a claim, not as verified work.