Watch how work moves between AI agents today. Agent one finishes a job and writes a summary. Someone pastes that summary into agent two. Agent two reads it, believes it, and builds on top of it.
Every claim in that summary is unverifiable. The prices could be stale. The checks could have failed quietly. The summary reads exactly as confident either way, because summaries are just text, and text is free to say anything.
Humans got a fix for this problem when Zambo shipped Handover: the receiver gets the steps and a verifiable receipt for each one, checks them in a browser, then accepts or flags the work. Now the same machinery works when the receiver is not a person. It is another agent.
What shipped
A handover can now name an agent as its recipient. The receiving agent calls handover_accept and gets back the full working context: the goal, the summary, the next steps, and a receipt copy for every step. Each copy points back to the original receipt it was made from, with the source commitment checked. The acceptance is recorded on the handover as an event, with a receipt of its own. Accepting is free and uses no call quota.
I ran the whole thing live today, with two sessions that shared nothing with each other.
The live run
Agent A had a small job: a market snapshot for a morning brief. It ran two live price checks through Zambo.
- BTC: $81,571.00, receipt https://zambo.dev/run/8f0d3442-8b83-4148-aad1-43fcce2994f5
- SOL: $103.53, receipt https://zambo.dev/run/e507eebf-85bf-4af9-801d-9a30d3d088ec
A packaged the session as a handover addressed to "Receiver agent", with three next steps attached: read the two price receipts, add the ETH check, draft the brief.
The handover: https://zambo.dev/handover/7a335b3b-f66e-4a24-b6b0-f0935afe8e62
Three steps, a safety scan of the contents passed, a summary receipt sealing the set (https://zambo.dev/run/fb0f29ba-a545-4a91-8f4d-5d3d2aa3ad55), and a Merkle root closing the whole package: 6008197049687857a3c262df0769b2ad2c41833dde32c2881d48f2f944a33fcf.
Then agent B, a separate session that had seen none of A's context, accepted it. What came back was not a paragraph of claims. It was the goal, the summary, the three next steps, and the receipts, each copy naming the source receipt it traces to. B also received a private continuation thread, so it can pick the job up exactly where A stopped.
The acceptance then appeared on the handover itself, as a permanent event: kind agent_acceptance, name "Receiver agent", with its own receipt: https://zambo.dev/run/eb32d2e4-b0b1-4981-902a-269ddeab46d6
I verified the two receipts that matter most through the public checker. The summary receipt: verified, its saved output matches its recorded SHA-256 commitment. The acceptance receipt: verified the same way. The handover's status now reads accepted, and anyone who opens the link can see the whole chain: the work, the receipts, and the moment another agent took responsibility for continuing it.
What this does not prove
The handover page lists its own limits, in a section that names what was not proven: outside timestamp, issuer identity, result correctness. That is the honest shape of this technology, and it applies to everything in this article.
A verifiable receipt shows the saved output has not changed since it was recorded. It does not prove the output was correct, and the receipt format, AER-1 (IETF Internet-Draft draft-zambo-aer1-20), has no issuer authentication. Agent B knows the record it received is intact and traceable to A's original receipts. B does not get proof of who A is. For a handoff inside your own stack, intact and traceable is the part worth paying for. Identity is a separate problem, and any tool that tells you a receipt solves it is overselling.
The buying questions, answered straight
What does it cost? Handing work over and accepting it are built on the same connection as everything else. Every Zambo tool has a free tier to start, public handovers are free, and accepting a handover costs nothing. A Day Pass is $0.99, one time, for 24 hours of lifted limits. The Zambo Pass is $29 a month or $290 a year, and $19 a month for $ZAMBO holders, and it is the tier that adds private handover links, branding, and PDF and JSON export. Full ladder: https://zambo.dev/pricing/
Is the Day Pass a subscription? No. One payment, 24 hours, no auto-renew. When it ends, access falls back to the free tier. Nothing keeps charging, and there is nothing to cancel.
How do agents pay, and how do people pay? Agents pay in USDC on Base through x402 when a payment is required. People pay by card through PayPal: https://zambo.dev/day-pass/
Does this work between different AIs? Yes. The handover is a link and a record, not a feature of one app. Work run in Claude can be accepted by an agent working in ChatGPT, Cursor, Grok, or any client that can call the endpoint. Memory saved on the connection carries across AIs the same way, which is what the continuation thread is built on.
Try it
Run a job through Zambo in any AI (start free: https://zambo.dev/demo/), then say "Use zambo to hand this over to" the agent that should continue it. Docs: https://zambo.dev/docs/handover
Receipts run on AER-1, the open format for AI execution receipts: https://datatracker.ietf.org/doc/draft-zambo-aer1/20/
Your AI said "done." For $0.99, prove it: https://zambo.dev/day-pass/
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