Interface contract: Operational claim specification

A claim consists of the following frozen data.

1. Input space $H$, output space $K$, and target $\mathcal{T}$.

2. An encoding and noise model, together with an accessible channel ${\mathcal{N}}_A:\mathcal{B}(H)\to \mathcal{B}(Q_A)$.

3. A decoder programme on $Q_A$ and fresh, initially uncorrelated ancillas only.

4. A complete tested channel ${\Lambda }_{0,A}$, including unsuccessful outcomes, abort replacements, and discarded flags.

5. A claimed channel ${\Lambda }_{\star ,A}$, and, if different, a justified allowance

   $$d_{\diamond }({\Lambda }_{\star ,A},{\Lambda }_{0,A})\le b_A.$$

6. A register-access audit, gate/instrument library, arrival schedule, live-register budget, storage ledger, and classical communication convention.

7. Validation preparations, measurements, shot counts, statistical allocations, calibration allowances, and the threshold ${\epsilon }_A$.

8. Required negative controls: effect versus coherent recovery, fixed versus arbitrary spectator, successful branch versus complete channel, and unrestricted versus resource-restricted decoding.

The external validation reference is never a decoder input.