ZBL contract replay receipts
Build and simulate a ZCT, save a receipt and verify deterministic replay.
ZBL SDK v0.5.0-preview.5 can save and verify a version 1 ZBR replay receipt. The format records the SHA-256 of the exact ZCT artifact, the initial state, every input and resulting state, and the fuel used per transition. Verification recomputes the result with the same artifact and versioned meter and compares all fields.
zebvix contract build counter.zct
zebvix contract receipt counter.zct counter.receipt.json 40 2 -1 1
zebvix contract verify-receipt counter.zct counter.receipt.json
Studio v0.3.2 provides both actions in the Contract workbench. Use a trusted workspace and enter paths relative to its root. Saving requires a new receipt filename. You can pass the artifact and receipt to a recipient for independent replay.
Version 1 accepts up to 32 transitions, caps input receipts at 16 KiB, charges up to 100,000 fuel per transition and limits total fuel to 1,000,000. Contract local slots use a fixed accounting charge. Fuel measures work inside ZBR. It is separate from ZBX validator gas and fees. A failed batch produces no successful receipt or persistent contract state. The existing simulate command retains its original JSON structure and per-transition limit.
The receipt provides reproducible evidence for the artifact and inputs it contains. Sender identity, signatures, finality and chain inclusion require separate proof. The ZCT format remains the offline ZBR target.