Conciseness

Dense, reference-style tables and code with no padded prose, but 'Common Mistakes' and 'Anti-Patterns' tables overlap and restate concepts Claude already knows (e.g. 'String errors -> thiserror types'), which is more than minor over-explanation. Not a 5 due to that redundancy; above 3 because the bulk is efficient.

Actionability

Provides fully executable, copy-paste-ready Rust (thiserror enum with is_retryable(), tokio-retry exponential backoff) plus a Quick Reference mapping each pattern to concrete crates (failsafe-rs, tokio-retry, backoff, tokio::time::timeout), covering the common cases.

Workflow Clarity

The numbered 'Thinking Prompt' (Who sees this? Can we recover? What context?) gives a clear decision sequence, and Trace Up/Trace Down structure navigation; no validation checkpoints are needed for a design-guidance skill, so it sits at clear-sequence-with-minor-gaps rather than the full-validated-workflow 5.

Progressive Disclosure

Well-organized with clear section headers and a 'Related Skills' cross-link table, but all 180 lines are inline with no bundle files or one-level-deep references, so it does not reach the well-signaled-external-reference 5 anchor; the under-50-line simple-skill exception does not apply.

Specificity

The single action verb 'designing domain error handling' is elaborated by a keyword list enumerating concrete sub-actions (error categorization, retry, fallback, circuit breaker, backoff, graceful degradation), listing several specific actions with only minor coverage gaps. Not a 5 because there is no comprehensive multi-action sentence, and above 3 because the keywords convey more than 1-2 actions.

Completeness

Explicitly answers both: 'what' via 'designing domain error handling' plus the elaborating keyword list, and 'when' via the explicit 'Use when designing domain error handling' trigger clause, so the missing-trigger cap does not apply.

Trigger Term Quality

Extensive natural keyword coverage including synonyms ('retry' / 'retry with backoff', 'transient vs permanent error') and bilingual terms (领域错误, 错误分类, 恢复策略, 重试, 熔断器, 优雅降级), matching the comprehensive-synonyms anchor.

Distinctiveness Conflict Risk

'domain error handling' design (Layer 2) is a mostly-distinct niche, but closely related skills (m06-error-handling, m09-domain) create minor overlap risk, fitting the 'mostly distinct; minor overlap' anchor rather than the minimal-conflict 5.