Conciseness

The body is dense and idiom-focused with tight code blocks and Go-specific rationale ('multiple init() functions run in declaration order... in filename alphabetical order — fragile'), but the 21-item 'Best Practices Summary' restates roughly ten items that the later sections then repeat in detail, which is trimming opportunity. Not 5 because of that deliberate duplication; not 3 because virtually every sentence carries non-generic guidance rather than padding.

Actionability

Mostly executable guidance: copy-paste-ready Go for functional options, init() avoidance, enums, package-level regexp, embed, defer Close, and context timeouts, with bad/good contrasts. Not 5 because a few sections give only prose or bare pointers — 'Retry logic MUST check ctx.Err() between attempts' has no code, and 'Database Patterns' and 'Compile-Time Interface Checks' are single-line redirects.

Workflow Clarity

The two 'Modes' provide brief sequencing ('ask the developer about their architecture preference before proposing patterns'; 'report findings before suggesting refactors'), but the skill is primarily a pattern reference: no explicit multi-step workflow, no validation checkpoints, and review-mode findings criteria are listed only as a one-line scan hint. Not 4 because checkpoints/sequences are implicit rather than 'mostly present'; not 2 because the mode structure does define a coherent order of operations. No destructive/batch cap applies.

Progressive Disclosure

The SKILL.md body stays an overview (core patterns with compact code) while detail is split across six real reference files — data-handling.md, resource-management.md, architecture.md, clean-architecture.md, hexagonal-architecture.md, ddd.md — all referenced one level deep with a 'Detailed Guides' table describing each file's scope, and cross-references to sibling skills for out-of-scope topics. All referenced paths exist on disk and none of the reference files nest further references.

Specificity

The description enumerates multiple concrete capabilities — 'functional options, constructor APIs, init() and global-state avoidance, enums, panic vs error decisions, resource management and lifecycle, graceful shutdown, timeouts and retries, streaming and iterators, and architecture styles (clean, hexagonal, DDD, flat)' — comprehensive coverage with no vague filler. Not below 5 because no significant capability area of the skill is missing from the enumeration.

Completeness

Both questions are answered explicitly: the 'what' is the long capability enumeration, and the 'when' is the concrete 'Apply when choosing between architectural patterns, implementing functional options, designing constructor APIs, setting up graceful shutdown, applying resilience patterns, or asking which idiomatic Go pattern fits a specific problem' clause — plus a 'Not for...' exclusion list. It clearly exceeds the 4 anchor, whose 'when' is present but less explicit.

Trigger Term Quality

Trigger phrases like 'implementing functional options', 'designing constructor APIs', 'setting up graceful shutdown', 'applying resilience patterns', and 'choosing between architectural patterns' match natural user phrasing, and 'Golang' plus named styles (clean, hexagonal, DDD) aid discovery. Not 5: some natural synonyms are absent (e.g., plain 'Go', '.go' file extension, 'interfaces', 'project structure'), so coverage is good but not exhaustive.

Distinctiveness Conflict Risk

Clear Go design niche with explicit de-scoping of adjacent territory — 'Not for wiring a DI container or comparing DI libraries... nor for error wrapping, errors.Is/As, or logging mechanics' — each redirecting to a named sibling skill, so mis-trigger risk against overlapping skills is minimal. No broader anchor fits better.