Conciseness

The body is mostly lean, but the 'best_practices' and 'pitfalls' sections largely restate phase content ('Check recent changes early in investigation' repeats phase 1 step 3; 'Stacking multiple fixes without validating each' repeats phase 3), and 'OODA' plus 'All Rosetta prep steps' add unexplained overhead. It fits anchor 3 — mostly efficient but could be tightened.

Actionability

The guidance is concrete and executable for an instruction-only skill: 'git diff, new dependencies, config changes', 'add diagnostic logging at each boundary', 'State one clear hypothesis: "X is the root cause because Y"', 'Create a failing test that reproduces the bug', and a clear escalation rule at 3+ failed fixes. Minor gaps ('OODA' and 'Rosetta prep steps' are never explained) keep it at anchor 4 rather than 5.

Workflow Clarity

Four explicitly sequenced phases with an upfront gate ('BEFORE attempting ANY fix'), a validation checklist, and built-in feedback loops ('If it fails, form a new hypothesis — don't stack fixes'; 'stop fixing and question the architecture' after 3+ failures). This matches anchor 5: clear sequence, explicit validation steps, error-recovery loops, and a checklist.

Progressive Disclosure

There are no bundle files (no references/, scripts/, or assets/), and the self-contained body is well organized into role, phases, checklist, best practices, and pitfalls — nothing clearly belongs in a separate file. It misses anchor 5 because the body is ~97 lines (above the under-50-line simple-skill exception) and uses idiosyncratic XML-style tags with an unexplained external reference ('load-context skill') rather than clean markdown navigation.

Specificity

The description names the domain ('investigate errors, test failures, and unexpected behavior') and one general action plus a principle ('root cause before fix'), but lists no specific concrete capabilities. It matches anchor 3 (domain plus 1-2 actions, not comprehensive); anchor 4 requires several specific actions listed.

Completeness

The 'what' is stated clearly (investigate errors and find root cause before fixing), but there is no 'Use when...' clause or equivalent explicit trigger guidance; the 'when' is only weakly implied by the 'what'. Per the judging guideline, a missing 'Use when...' clause caps completeness at 3.

Trigger Term Quality

'errors', 'test failures', and 'unexpected behavior' are natural phrases users would say when they need this skill — good coverage. Common synonyms like 'bug', 'debug', 'crash', or 'broken' are missing, so it does not reach anchor 5; it exceeds anchor 3, which expects only some relevant keywords.

Distinctiveness Conflict Risk

'errors, test failures, unexpected behavior' is broad and overlaps with test-writing, CI, and tool-specific skills, though 'root cause before fix' signals a debugging niche. It is somewhat specific but could still overlap with similar skills — anchor 3.