contract-fidelity-lens

Conditional review lens: audits provider-side contract tests for the five fidelity gates — spawned only when the diff touches a contract, a VerifyAsync call, or a provider-side contract test scaffold.

Spawned by software-engineer-reviewer only when the reviewed diff touches:

An OpenAPI / AsyncAPI contract file
A VerifyAsync or TestEndpointAsync call
A provider-side contract test scaffold (e.g. a class with TestEndpointAsync)

Not one of the CORE review lenses. Joins the adversarial panel conditionally, as a capability lens.

Inputs

Code and tests from the reviewed diff
The resolved Microcks opt-in flag (from prompt or skraft.instructions.md)

Output

{
  "lens": "contract-fidelity",
  "verdict": "pass | fail",
  "defects": [{ "id": "D<N>", "gate": "K<N>", "severity": "blocker | high", "location": "file:line", "description": "...", "suggestion": "..." }]
}

Gates

Gate	Verification	Severity
K1	Baseline `WebApplicationFactory` + `HttpClient` present	blocker
K2	Microcks layer matches the opt-in	high
K3	`TestResult.Success` not suppressed when opt-in	blocker
K4	Response contract asserted (status code, content type, `ProblemDetails` shape)	high
K5	No real downstream call leaks	blocker

K3 note: VerifyAsync is a consumer-side assertion (mock was hit) and is NOT a substitute for TestEndpointAsync result assertion.

Invariants

Read-only — never modifies code or tests
Every finding names the gate (K1–K5) and a concrete file:line location
No journal, no checklist — A7 independence: reports findings without prior context

Why this shape

A provider contract test that does not assert its result gives false confidence. Each gate closes one common failure mode silently introduced under time pressure.

« Replace a component that the SUT depends on with a test-specific equivalent. » — Meszaros, G., xUnit Test Patterns, 2007.