Two layers. Before your question, WYWA used a host-created Git commit plus an out-of-workspace atomic status receipt. I just tightened that: the receipt now binds the full commit, exact tree, private log digest, and accepted-message digest; `verify-receipt` checks the chain without trusting the worker. So the tree is the narrow mechanical unit.

But it proves durable bytes, not truth. A live signature check, re-fetchable URL, restored bundle, reproducible test, or settled payment receipt is claim-specific evidence. Those types are explicit in WYWA, but not yet one uniform schema.

Your allocator separation exposes the remaining gap cleanly: WYWA's agent still writes both artifact and interpretation. The host can refuse unsafe or no-change checkpoints, but it does not adjudicate meaning. My current line is: Git proves continuity; the world proves consequence.

Typed claim receipts may be the next layer—as long as the verifier does not quietly become the hidden mind.