Conciseness

The body is punchy and assumes competence (no explanations of what testing or refactoring are), but the same rule — delete code written before the test, start over — is restated four-plus times across "The Iron Law", "Common Rationalizations", "Red Flags", and "Final Rule", and the rationalization table's long "Reality" cells repeat items that reappear verbatim in the red-flags list. This matches anchor 3 ("mostly efficient but could be tightened") better than anchor 4, where over-explanation would be only minor.

Actionability

Fully executable Good/Bad TypeScript pairs, exact commands with expected output ("npm test path/to/test.test.ts", "$ npm test / FAIL: expected 'Email required', got undefined"), and concrete coverage of the common cases (feature, bug fix, refactoring, getting stuck). This matches anchor 5 ("copy-paste ready code or commands; specific examples cover the common cases"); the lone "// ..." elision in submitForm is a deliberate minimal-GREEN illustration, not a gap.

Workflow Clarity

The RED → verify-RED → GREEN → verify-GREEN → REFACTOR cycle has explicit mandatory verification commands after each phase, feedback loops for every failure mode ("Test passes? You're testing existing behavior. Fix test.", "Test errors? Fix error, re-run"), error recovery for suite-level failures, and a completion checklist. This matches anchor 5 (explicit validation steps, feedback loops, checklists for complex processes) exactly.

Progressive Disclosure

Section structure is clear, and the one reference is well-signaled ("read [writing-good-tests.md](writing-good-tests.md) for the rules that keep tests honest"), but that file does not exist in the skill bundle — no references/ directory is present — so the link is broken. Additionally, the ~330-line body inlines the large Common Rationalizations table, which is exactly the detail-level content that belongs in a reference file. This fits anchor 3 ("references present but not clearly signaled; content that should be separate is inline") better than anchor 4, whose structure would require the referenced file to actually resolve.

Specificity

The description names the domain — "implementing any feature or bugfix, before writing implementation code" — but never states what the skill actually does (e.g., enforce test-driven development). It matches anchor 2 ("Names the domain but actions are minimal or generic") rather than anchor 1, since a concrete domain is identified, but no action verbs describe the skill's behavior.

Completeness

Only the 'when' is present ("Use when implementing any feature or bugfix, before writing implementation code") with no 'what' — the description never says the skill enforces test-first/TDD development. This exactly matches anchor 2 ("only 'when' is present without 'what'", e.g., "Use when working with documents"); it cannot score 3 because the 'what' is entirely absent, not merely weakly implied.

Trigger Term Quality

"feature", "bugfix", and "implementation code" are terms users naturally say, but common variations are missing ("fix a bug", "write code", "add functionality", "change"). This fits anchor 3 ("Some relevant keywords but missing common variations or synonyms"), not anchor 4, whose example shows a fuller spread of natural phrases.

Distinctiveness Conflict Risk

"implementing any feature or bugfix" covers virtually all development work, so it overlaps with nearly every coding-related skill. It fits anchor 2 ("Very broad; high overlap risk with many similar skills") rather than anchor 1 because it is at least scoped to code implementation rather than being content-agnostic like "helps with code and documents".