Direct answer
Claude Proof of Work
Claude does not issue a checkable record of its own work. The conversation is Claude account of what Claude did, stored in Claude history, and a client reading it is taking the transcript at face value. Proof of work is stricter: each executed step saved when it ran, in a record someone else can verify without trusting the transcript. Connect Claude to Zambo, the verifiable work layer for AI, and the tool calls Claude makes through the Zambo MCP endpoint each produce a verifiable receipt. Anyone checks it free at zambo.dev/verify. This page covers the starting point, the setup for the app and the API, and the proof of execution vs logs distinction in full.
Updated October 20, 2026.
The honest starting point: what Claude gives you today
Claude is excellent at the work: long documents, careful reasoning, clean code, patient revision. What it hands back as a record is the conversation itself. The conversation shows the final answer in polished form. It does not independently show which tools ran, what a tool returned, or whether the text you forward to a client is the text that came out of the session. Share a project or export a chat and the reader still has exactly one source for every claim: the transcript.
That gap shows up in ordinary places. A client asks what the research covered and the answer is a scroll. A team lead asks whether the analysis used live data or training knowledge and the transcript cannot settle it. A freelancer sends screenshots of a Claude session and watches the client squint at cropped images of a chat window. None of these people doubt Claude ability. They doubt the evidence, because the evidence and the claim are the same document. The fix is not a better transcript. The fix is a record filed outside the transcript, at the moment each step executes.
How to route Claude work through Zambo
Claude supports MCP connectors, which makes the route direct. Add https://zambo.dev/mcp in Claude connector settings, one URL and no key, and the Zambo tools appear alongside the conversation. When Claude needs a live price, a source check, a page audit, an extraction, or any of the 153 tools on the endpoint (35 on the default surface), it calls the tool, the call executes through Zambo, and the saved result is filed with a verifiable receipt at that moment. Claude still writes, reasons, and revises. The executed steps underneath the writing are what get recorded.
For developers on the Claude API, the pattern is the same one level down: calls your application makes through the Zambo endpoint return their results with receipts attached, so an automated pipeline files the same records an interactive session does. Claude proof of work API, in practice, means your application records each executed step as it goes rather than reconstructing a report afterward. Keep the habit simple: decide which steps in a job are the load bearing ones, the checks, the fetches, the computations, and make sure those run through the connected tools. The drafting around them needs no receipt; the evidence under the drafting does.
When the job is finished, assemble the record into a handover: one link with the goal, the steps in order, the outputs, and the receipt on each step. The client opens it in a browser with no account, checks any receipt free at the verifier, and accepts the job or flags one step. The worked shapes are public: an open handover waiting on its client, and an accepted one showing the closed state, both linked from the box at the top of this page.
What a receipt for Claude work looks like
A receipt names the tool that ran, the input it ran on, the result that was saved, and the time it ran. Checking it at zambo.dev/verify recomputes the saved result and compares it with the filed record. Match: the result in front of you is the result that came back when the step executed. Mismatch: the check fails in the open, and anyone can see it fail. That second property is what makes the first one worth anything: a check that cannot fail proves nothing.
On its own, one receipt covers one step. The value compounds across a job: research steps, source checks, drafts produced by tools, and deliveries each carry their own record, and the handover chains them into the order the work actually happened. A client disputing a step lands on that step, with its input and output open, instead of reopening the whole engagement. A team reviewing Claude work across a week reads records, not chat archaeology. That is Claude receipts as a working system rather than a slogan.
Proof of execution vs logs, for Claude specifically
The Claude proof of work vs logs question and the Claude proof of execution vs logs question are the same question, and it deserves a precise answer. A Claude conversation, an exported transcript, and an application log are all logs: records kept by the system about itself, held by the party presenting them, editable in principle by that party. They are honest tools for honest debugging. As evidence for a second party, they ask that party to trust the keeper, which is the very thing under discussion in a dispute.
Proof of execution inverts the trust. The record is filed at execution time through Zambo, in the open AER-1 format (IETF Internet-Draft draft-zambo-aer1-24), and verification is a recomputation anyone can run at the public verifier. The keeper is not consulted and cannot quietly amend the past: change one character of a saved result and its check fails. When a client asks for proof of execution for clients, this is the deliverable they mean even if they use looser words: not your notes about the run, but a record of the run they can test themselves.
Claude receipts without screenshots
Screenshots of Claude sessions are the weakest common proof: cropped, timeless, stageable, and unreadable at volume. Claude receipts without screenshots replace the picture with the record. The client opens the handover, reads the actual outputs, and clicks through to verify the steps that matter. Nothing is cropped because nothing is an image. The record also travels better than a screenshot folder: one link in the delivery email, the same link next to the invoice, the same link in the dispute thread six weeks later, still checking the same way.
There is a craft point here too. Assembling a handover forces a final read of your own job: goal stated plainly, steps in order, open items listed as open. Freelancers report that the packet itself, before any verification happens, already ends most delivery arguments, because the client can finally see the shape of the work. The receipts then do the deeper job: they make the visible shape checkable.
Notes for your situation
The searches behind this page come in flavors. The record does not change; what changes is who checks it and why:
Claude proof of work for developers: file receipts from the API path: calls routed through the Zambo endpoint return results with receipts, so your pipeline accumulates a verifiable trail as a byproduct of running.
Claude proof of work for teams: give the team one link per job. Reviewers check steps instead of requesting screen shares, and the record survives staff changes because it never lived in one person chat history.
Claude proof of execution for clients: the client facing packet is the handover: goal, steps, outputs, receipts, and an Accept control only the client can use. That acceptance is itself filed on the record.
Claude receipts for freelancers: attach the handover link to the invoice. When a client says they never received the work, the record, not your memory, answers.
Claude receipts for small business: a small business owner checking an employee or contractor AI work opens the same link and runs the same free check. No tooling to buy for the checking side.
Claude receipts for teams: weekly review becomes record review: open the week handovers, spot check receipts, and spend the meeting on the work instead of on reconstructing it.
Claude verifiable receipt: the receipt is verifiable in the literal sense: a stranger with a browser can recompute it at zambo.dev/verify and watch it pass or fail. No account, no fee, no permission from you.
What it costs
Public handovers are free to send and free for the client to open. For $0.99, a Day Pass covers 24 hours of recorded work through the Zambo MCP at https://zambo.dev/mcp, 153 tools in total with 35 on the default surface. Ongoing use is the Zambo Pass at $29 a month or $290 a year, and $19 a month for $ZAMBO holders. Humans pay by PayPal or card through PayPal; agents pay USDC on Base through x402. Frame it against the problem on this page: one payment turns a day of AI work from a claim into a record that anyone can check, which is the difference between arguing about a job and closing it.
Honest limits
Three edges, stated plainly. First, a verifiable receipt proves the saved result was not changed after the fact; it never proves the work was correct, well judged, or worth what you charged. The client still judges whether the reasoning was sound or the draft was any good. Second, the record only covers steps that ran through Zambo: work Claude did entirely on its own, outside the routed calls, has no receipt, and an honest packet lists that work as unchecked instead of pretending it is covered. Third, a receipt is a record, not a legal contract or a payment: pair it with your normal agreement and invoice, and let each document do its own job. AER-1, the receipt format underneath, is an IETF Internet-Draft (draft-zambo-aer1-24), not a finalized standard.
Frequently asked questions
What is Claude proof of work?
Claude proof of work is a checkable record of the steps Claude executed for a job, filed when the steps ran rather than described afterward. Claude itself keeps only the conversation, which is its own account of the work. Connect Claude to Zambo at https://zambo.dev/mcp and each tool call through the endpoint produces a verifiable receipt. The receipts for a job travel in one handover link, and anyone can check any of them free at https://zambo.dev/verify/ with no signup.
Does Claude itself issue Zambo receipts?
No. Claude does not issue Zambo receipts, and this page will not pretend otherwise. Zambo records work that runs through the Zambo MCP endpoint: when Claude, connected as an MCP client, calls a Zambo tool, Zambo executes the call and files the saved result with a receipt. Steps Claude performs entirely inside its own conversation, with no routed tool call, leave no Zambo record. If you need a step covered, run that step through the connected tools. The boundary is simple and it is the honest one.
What is the difference between Claude logs and proof of execution?
A Claude transcript or application log is a record the system keeps about itself, presented by the party it describes, and editable by whoever holds it. Proof of execution is filed at the moment a step runs through Zambo, in the open AER-1 format, and anyone can recompute it at the public verifier without trusting the keeper. Change a character in a saved result and the check fails. Logs are for debugging your own work. Receipts are for showing someone else, which is why clients ask for execution proof rather than logs.
How do I give a client proof of execution from Claude?
Connect Claude to https://zambo.dev/mcp, run the load bearing steps of the job through the Zambo tools so each one files its receipt, then send the client the handover link for the job. The client opens it with no account, reads the goal, steps, and outputs, and checks any receipt free at https://zambo.dev/verify/. They accept the job or flag a specific step, and that decision is written into the record. You cannot accept your own handover, which is what makes the client acceptance worth having.
How much does Claude proof of work cost?
Checking a receipt is free at https://zambo.dev/verify/, and public handovers are free to send and free to open. For $0.99, a Day Pass covers 24 hours of recorded work through the Zambo MCP at https://zambo.dev/mcp, which runs 153 tools in total with 35 on the default surface. Ongoing use is the Zambo Pass at $29 a month or $290 a year, and $19 a month for $ZAMBO holders. Humans pay by PayPal or card through PayPal; agents pay USDC on Base through x402.