habitatThe five receipts¶
In short. Each receipt asks one question of a real public record and answers it in a way you can recompute. Each has a page on habitat.ooo, a kit, and an entry in a public log made by the Foundation.
| receipt | the question | the record | status |
|---|---|---|---|
| Agent traces | Did the agent's own actions leak into its record of what happened? | 28 coding-agent sessions donated to a public collection (CC-BY) | live |
| Keep-out | Did a readable record shape what the system learned? | the same sessions | live, edition 2 |
| Take-out | Did the erased record actually leave the state? | the same sessions | live, edition 2 |
| Point-in-time | Did the backtest's state ever see the future? | Ken French daily research factors, 2018 to 2022 | open question |
| Revision materiality | Did the revision change the history, or only its packaging? | CFPB mortgage disclosures, Washington DC, 2022, two pulls | open question |
"Open question" means the receipt runs on real data, but its method still has a question, which its page states (the receipt pages call this "frontier").
What every receipt does¶
Each answers two questions about its record:
- Does it hold? A change that shouldn't matter, such as re-sorting the rows or re-exporting the file, must leave the published digest exactly the same. That one is decided byte for byte. It needs no floor.
- Does a real change show? A change that should matter must move the record further than the record's own floor. The floor and how it was read are published with the result.
What every receipt does not do¶
A receipt verifies a stated property of a record. It doesn't verify that an output is correct, and it doesn't certify fairness or independence. A person decides what a result means.
Editions¶
When a receipt's method is corrected, the new edition is published beside the old one, and the old one stays at its address. Keep-out and take-out are in their second edition (20 October 2026): a change now counts only when it is larger than the record's own measured floor; edition 1 used a fixed bound instead. Their first editions stay in place, still anchored and still checkable.
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