git:20260803.7558807 to git:20261020.17ad730

---

name: verify-serving-parity

description: Verify identical weights across serving lanes using observed render fingerprints, paired samples, and explicit evidence status.

---

# Verify serving parity

Use `src/serving-parity` as a pure, offline verifier. Every lane must provide an

observed render fingerprint, contract fingerprint, parser evidence, and an

artifact reference plus SHA-256. Outputs contain references and hashes only;

never place prompts, responses, traces, labels, credentials, or weights in a

parity artifact.

Declare a meaningful minimum paired sample before scoring (default: 20). A

failed preflight refuses comparison. `observed`, `weak`, `deviation`, and

`failed` evidence status must remain visible, and the output includes

`understudy.promotion_receipt.v1` compatibility metadata for downstream gates.

Run only against synthetic or already-approved local artifacts; this verifier

makes no provider calls and does not access holdout data.

## Safety Gates

- Compare at least two uniquely named lanes using the same artifact hash,

observed render fingerprint, contract fingerprint, protocol, sampling, stop

sequences, parser contract, and frozen task IDs.

- Predeclare a paired-sample floor and equivalence band. Missing pairs,

duplicate task IDs, deviations, weak evidence, or invalid hashes fail closed.

- Keep prompts, responses, labels, traces, credentials, and weights out of the

parity artifact. A passing parity receipt is necessary but not sufficient for

promotion.

## Resolve CLI

There is no public CLI yet. Build the package and call

`preflightServingParity` followed by `scoreServingParity` from

`dist/serving-parity/index.js` in an offline script. Do not score when preflight

refuses the evidence.