Spec-Driven Implementation Evaluation

Evaluate a spec-driven-development (SDD) effort against a PRD case by case (acceptance criterion by acceptance criterion), scoring implementation and tests separately, and roll up to a single comparable final grade. Designed for benchmarking: the same PRD evaluated across different SDD frameworks — and the same effort evaluated twice — must yield comparable, reproducible numbers.

Two subjects, two questions

This eval answers two independent questions, and keeps their verdicts separate because they fail independently:

1. How good is the framework at respecting and extracting requirements? — Did it honor the PRD and stay in bounds (respect: Final implementation side + Scope S), and did it surface the implicit requirements the PRD only implied, without noise (extract: Elicitation E)?
2. How good is the harness at ensuring they are all implemented? — Does the test suite prove every sanctioned requirement is actually built (T + Engineering Gates G)?

The linkage that makes "all implemented" well-defined: the harness is held accountable for the full sanctioned requirement set = PRD acceptance criteria ∪ valid E-additions. A valid requirement the framework extracted but the harness never tests is a harness miss (T), not a framework miss (E keeps the extraction credit). Extraction defines the verification target.

Scoring is checklist-based: every criterion is decomposed into atomic binary (MET / UNMET) checks, each backed by file:line evidence. Binary decomposition is the design choice that makes the grade reproducible — graded/Likert scales (is this a 3 or a 4?) are the dominant source of evaluator-to-evaluator disagreement; binary checks raise inter-evaluator agreement to roughly human level. Partial credit is derived from the fraction of checks met, never judged on a sliding scale.

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