MobileBuildMCP Snapshot Fixture Review

Review guardrails for fixture and snapshot contract integrity.

Review scope

• Review-only by default.
• Do not edit product code unless the user explicitly requests implementation changes.

Files to inspect

• src/snapshot-tests/__fixtures__/**
• src/snapshot-tests/contracts.ts
• src/snapshot-tests/fixture-io.ts
• src/snapshot-tests/__tests__/fixture-io.test.ts
• src/snapshot-tests/__tests__/json-normalize.test.ts
• src/snapshot-tests/__tests__/json-fixture-schema.test.ts
• xcodebuildmcp.com/app/docs/_content/testing.mdx

Guardrails

• Fixture updates map to intentional behavior changes.
• Do not update fixtures only to make tests pass.
• MCP, CLI, and JSON fixture updates stay aligned.
• JSON fixtures preserve stable structured output envelopes.
• Volatile values are normalized in code, not patched ad hoc in fixtures.
• Missing fixtures are generated through the snapshot update flow.
• Verify project-defined normalization sentinels in normalization code and tests before reporting them as implausible fixture values. In particular, 99999 is an intentional sentinel for volatile UI capture counts.
• Group every occurrence of the same root cause into one finding and list the affected fixtures. Do not emit separate findings for equivalent CLI, MCP, text, or JSON drift.
• Do not repeat a finding that is already resolved by the current diff.

Review limits

• Review the changed fixtures and the directly relevant normalization or contract code only.
• Do not run snapshot or smoke suites as part of an automated PR review.
• Prefer one high-confidence cross-fixture finding over multiple speculative discrepancies.