Conciseness

At ~36 lines of dense, non-padded guidance, every sentence adds judgment Claude doesn't have: concrete defect patterns, guard-fidelity comparison instructions, threshold criteria, and reporting requirements. No basic concepts (what a retry or timeout is) are explained, matching the 'every token earns its place' anchor.

Actionability

Concrete, executable guidance throughout: literal code patterns to search for ('catch (e) {}', '.catch(() => {})', 'no finally, defer, using, or context manager'), a specific procedure in Method (trace every external call's failure to callers, read the AGENTS.md/CLAUDE.md chain), and concrete finding requirements ('Point to the line missing the protection'). Per the scoring note, absence of code in an instruction-only skill is not penalized when guidance is this actionable.

Workflow Clarity

For a single-purpose review skill, the sequence is unambiguous: Scope defines what to look for, Method defines how to trace and prioritize, Threshold provides explicit include/exclude validation criteria for findings ('Report a gap when... Do not report internal pure functions...'), and Reporting defines output format. The Threshold section acts as the validation checkpoint for findings, and the operation is non-destructive so no stronger feedback loop is needed.

Progressive Disclosure

The skill is under 50 lines, needs no external references (none exist in the bundle), and is organized into five well-labeled sections (intro, Scope, Method, Threshold, Reporting) that each stay at overview altitude. This matches the guideline for short simple skills scoring 5 with well-organized sections.

Specificity

The description lists multiple specific concrete actions — 'missing error handling on I/O boundaries, unbounded retries, missing timeouts, swallowed errors, resource leaks on error paths, cascading failures, and CI or deploy guards that do not mirror production' — giving comprehensive coverage of what the skill reviews. Not 4 because the enumerated defect categories leave no minor gaps in what/coverage.

Completeness

It explicitly answers both: what ('Review a code change for missing error handling on I/O boundaries, unbounded retries, missing timeouts...') and when ('Use when reviewing for reliability, failure modes, partial failures, or graceful degradation') with concrete trigger phrases. This matches the anchor-5 example structure exactly.

Trigger Term Quality

Triggers include natural phrases users would say: 'reviewing for reliability, failure modes, partial failures, or graceful degradation', plus 'error handling', 'timeouts', 'retries', 'resource leaks' in the capability list. Not 5 because common synonyms users might use — 'resilience', 'robustness', 'stability', 'availability' — are absent.

Distinctiveness Conflict Risk

It carves out a clear niche (reliability/failure-mode review of code changes) with distinctive triggers ('failure modes, partial failures, graceful degradation') that separate it from general code-review or security-review skills. Not 4 because the overlap risk with other review lenses is minimal, not 'minor overlap with closely related skills' in a material way.