Feature Definition (200 Series)

The 200 series turns a feature request into a set of reviewable, implementation-ready artifacts. Each skill in this series produces a document that guides and constrains the implementation run that follows.

The four steps

Skill	Output	Required
201-high-level-design	overview.md — scope, user journey, acceptance criteria	Core
202-spec-design	specs.feature — numbered Gherkin scenarios	Core
203-implementation-design	implementation.md — repo-grounded implementation plan	Optional
204-feature-validation	Chat-only readiness review across all artifacts	Optional

The minimum viable design loop

201 followed by 202 is the practical minimum before a 301 implementation run. The optional steps (203 and 204) add a persisted implementation plan and a pre-coding readiness review — valuable on complex features, overhead on simple ones.

All outputs go to the same path

Every skill in the 200 series writes to .specflow/features/<fid>-<feature-slug>/. The files accumulate across the loop and 301 reads all of them before coding.

.specflow/
  features/
    F003-invoice-approval/
      overview.md          ← written by 201
      specs.feature        ← written by 202
      implementation.md    ← written by 203 (optional)

Skills in this series

• 201 High-Level Design — define the feature in plain language
• 202 Spec Design — write the Gherkin behavior scenarios
• 203 Implementation Design — produce a codebase-grounded implementation plan
• 204 Feature Validation — cross-artifact readiness review before coding