Conciseness

The body is ~20 lean lines of pure convention statements ("One component per file: `ComponentName.tsx`... co-located with `ComponentName.module.scss` and `ComponentName.test.tsx`", "`strict` stays enabled in `tsconfig.json`; no `as` casts") with zero explanation of concepts Claude already knows. Every token earns its place, matching the score-5 anchor; there is no padding to trim as score 4 would require.

Actionability

Guidance is concrete and executable in the main — specific file naming, export naming (`ComponentNameProps`), the strict/no-cast rule, and dompurify for sanitization — but there are no example snippets (no sample component skeleton, props interface, or RTL test) and the verification commands are deferred ("Resolve the exact commands via the **codebase-tool** slot") rather than given. This sits between the score-4 anchor (mostly executable with minor gaps) and score 5 (copy-paste ready examples covering common cases); the missing worked example keeps it at 4.

Workflow Clarity

There is a clear two-phase flow — apply Conventions, then "Lint, typecheck, test, and build must all exit zero" provides an explicit validation checkpoint — but no error-recovery loop (what to do when a check fails) and no explicit sequencing language. This matches the score-4 anchor (clear sequence, most checkpoints, minor validation gaps); score 5 would require explicit fix-and-retry feedback loops, and this is not a destructive/batch operation that would impose the cap at 3.

Progressive Disclosure

The skill is under 50 lines, has no bundle files (references/, scripts/, assets/ are absent), and the body is organized into three well-labeled sections (Conventions, Verification, Security) with only clearly signaled one-level pointers to other skills ("see **api-patterns**") and a project file (`.opencastle/project.instructions.md`). Per the rubric's simple-skill exception, this earns the score-5 anchor: well-organized sections with no need for external references.

Specificity

"Enforces React-specific patterns: functional components with hooks, TypeScript prop interfaces, CSS Modules co-location, React Testing Library behavioral tests" lists multiple concrete capabilities covering the domain (components, props typing, styling, testing) with no vague padding. This matches the anchor for multiple specific concrete actions with comprehensive coverage, and exceeds the score-4 anchor only in coverage completeness, not in kind.

Completeness

It explicitly answers both: what ("Enforces React-specific patterns: functional components with hooks, TypeScript prop interfaces, CSS Modules co-location, React Testing Library behavioral tests") and when ("Use when creating React components, writing custom hooks, structuring component folders, applying RTL test patterns, or wiring TypeScript prop types"). Both are concrete and explicit, matching the score-5 anchor exactly; score 4 would need a weaker or less specific 'when' clause, which is not the case.

Trigger Term Quality

"Trigger terms: React, .tsx, component, hook, RTL, jsx, useState, useEffect, prop interface" covers natural user vocabulary plus a file extension (.tsx) and API-specific names (useState, useEffect). This mirrors the score-5 anchor pattern (e.g., "PDF files, PDFs, forms, document extraction, .pdf") — comprehensive coverage including synonyms and extensions; score 4 would require a noticeably missing common term, and none is evident.

Distinctiveness Conflict Risk

The niche is unambiguous React frontend work: .tsx, jsx, useState, useEffect, RTL, and hooks are React-exclusive signals, so it is unlikely to fire for a generic TypeScript or testing skill. It has a clear niche with distinct triggers and minimal conflict risk per the score-5 anchor; the only faint overlap is 'TypeScript prop types', which is not enough to drop to the score-4 'minor overlap risk' anchor.