Conciseness

The ~30-line body is pure directive ("Re-read AGENTS.md, the active plan, the current branch, and the complete diff"; "trace the call site before you accept a bug claim") with zero concept explanations or padding — every token earns its place, matching anchor 5 ('Lean and efficient; assumes Claude's competence'). Not 4 because there are no instances of over-explanation left to trim.

Actionability

Concrete, executable guidance throughout for an instruction-only skill: exact file paths ('docs/development/quality-gates.md', 'docs/development/review-routing.md', 'CONTRIBUTING.md'), an explicit decision rule ("A defect or an unfinished part of the task under 'Possible follow-ups' or 'Known limits' is a BLOCK"), and fixed labels (APPROVE, CONCERN, BLOCK). Not 4 because the common conditional cases ("When runtime behavior changed", "When the change rejects input that was accepted before") are covered with specific instructions, leaving no gaps.

Workflow Clarity

Nine steps in coherent order (context, gates, reviewers, review areas, PR-body check, behavior comparison, finding filter, classify, fix) with an explicit feedback loop ("Fix every block, rerun the blocking reviewer, and update verification") and a verification mandate ("Review the actual source and live output. Do not infer correctness from a green compile") — matching anchor 5's 'explicit validation steps; feedback loops for error recovery'. Not 4 because checkpoints (classification, verification notes, rerun loop) are explicit rather than minor-gapped.

Progressive Disclosure

The skill is under 50 lines with no bundle files (no references/, scripts/, or assets/ exist) and is organized as a clean numbered workflow, so it qualifies for the simple-skill exception (5 with well-organized sections). Detail is correctly deferred one level deep to clearly signaled project docs ('docs/development/quality-gates.md', 'CONTRIBUTING.md'); nothing that belongs in a separate file is inlined. Not 4 because references are clearly signaled and organization has no gaps.

Specificity

"Perform Fallow's comprehensive pre-merge review" names the domain (pre-merge review) with a single action, matching anchor 3 ('Names domain and 1-2 concrete actions, but not comprehensive') — 'comprehensive' asserts breadth without stating what the review covers (gates, reviewer routing, classification). Not 2 because the domain and action are more concrete than 'Processes PDF files'; not 4 because no several specific actions are enumerated.

Completeness

Both parts are explicit: what ("Perform Fallow's comprehensive pre-merge review") and when ("Use after implementation or when asked to review a branch, pull request, or diff") with concrete triggers. Not 5 because the what is a single high-level action where 'comprehensive' claims scope rather than stating capabilities, unlike anchor 5's enumerated actions; not 3 because the 'Use when' clause is fully explicit rather than missing or weakly implied.

Trigger Term Quality

"review a branch, pull request, or diff" plus "after implementation" and "pre-merge" are natural phrases a user would say, matching anchor 4 ('Good keyword coverage; a few natural terms missing'). Not 5 because common variations are absent ('PR', 'code review', 'changes', 'before merging'); not 3 because multiple natural trigger terms are present, not just domain jargon.

Distinctiveness Conflict Risk

"Fallow's ... pre-merge review" scopes the skill to a clear project niche with a distinct timing trigger, matching anchor 4 ('Mostly distinct; minor overlap risk with closely related skills'). Not 5 because "review a branch, pull request, or diff" would also fire a generic code-review skill; not 3 because the project-scoped framing is more specific than 'Works with document files'.