The core four-phase process is concrete, but the body is padded with motivational exhortation Claude already knows ('Random fixes waste time and create new bugs', 'Violating the letter of this process is violating the spirit of debugging'), an unverifiable 'Real-World Impact' stats section, and a 'When to Use' block that duplicates the description. Not a 3 because substantial trimming would preserve clarity; not a 1 because the procedural core earns its tokens.

Provides concrete numbered phase steps and a copy-paste-ready bash instrumentation block (e.g. 'security list-keychains', 'codesign --sign "$IDENTITY" --verbose=4'), giving specific executable guidance for an instruction-style skill.

The four phases are explicitly gated ('You MUST complete each phase before proceeding to the next') with validation checkpoints (failing test case first, verify fix, count failed attempts) and clear feedback loops back to Phase 1 when a hypothesis fails.

References to root-cause-tracing.md, defense-in-depth.md, and condition-based-waiting.md are clearly signaled and one level deep, but none of those files exist in the bundle, so navigation is broken. Not a 3 because well-signaled references are undercut by missing targets; not a 1 because the SKILL.md is itself a reasonable overview with clean sectioning rather than a monolithic wall.

Lists multiple concrete actions via the 'four-phase process (investigate, analyze patterns, hypothesize, implement)', matching the anchor for naming several specific concrete actions rather than vague language.

Explicitly answers what it does ('Enforces systematic root-cause investigation before any fix attempt, using a four-phase process...') and when to use it ('Use when encountering bugs, test failures...') with explicit triggers.

Covers natural terms users would say ('bugs, test failures, build errors, unexpected behavior, performance problems, or integration issues') plus situational triggers ('under pressure', 'quick fix seems obvious', 'previous fix attempts have failed').

Occupies a clear debugging/root-cause niche with distinct triggers and an explicit negative trigger ('DO NOT TRIGGER for new feature development or refactoring without a known defect') that prevents misfiring. Not the level below because it is clearly distinguished from generic code skills rather than merely 'somewhat specific'.