Conciseness

The body is bullet-based and terse, but the second half (Philosophy, Procedure, Validation, Constraints, Anti-patterns) reads like a second concatenated template with generic boilerplate Claude already knows ('Optimize for clear, verifiable outcomes', 'Redact secrets... by default', 'Silent ignored errors usually become runtime bugs'). Mostly efficient, but noticeable trimming and consolidation is possible — not the anchor-2 'noticeably verbose' since no section is padded prose.

Actionability

There is one complete, executable code example (ParsePort) and concrete directives ('Return wrapped errors with %w', 'Return concrete structs from constructors'), but the execution-critical parts are vague: 'Re-run the highest-signal validations' and 'Run the relevant local checks' never name commands like 'go test ./...' or 'go vet'. Some concrete guidance, but key details are missing.

Workflow Clarity

The Procedure section gives a clear 1-2-3 sequence and the Validation section names a fail-fast/re-run loop, so it is above anchor 2. But the validation checkpoints are abstract ('highest-signal validations', 'relevant local checks') rather than explicit commands, so checkpoints are named but not concretized — anchor 3's 'sequence present but checkpoints missing or implicit'.

Progressive Disclosure

The deep-guidance reference is well signaled with a 'Read when' condition, but the referenced path 'Infrastructure/references/deep-guidance.md' does not exist in the bundle — the actual file is 'references/deep-guidance.md' — so navigation is broken as written. Additionally the Table of Contents omits six later sections (Philosophy through References and assets). Some structure, but organization gaps and a non-resolving reference keep it at anchor 3 rather than 4.

Specificity

The description names the domain ('working with Go codebases') and lists actions in the trigger clause ('writing, debugging, or exploring Go code, including reading dependency sources'), but the what is framed as generic 'Best practices' rather than concrete capabilities like the anchor-4 pattern of verb-plus-object actions, so it sits at 'names domain and some concrete actions, but not comprehensive'.

Completeness

It explicitly answers both: what ('Best practices for working with Go codebases... including reading dependency sources and documentation') and when ('Use when writing, debugging, or exploring Go code') with a concrete 'Use when' trigger clause. It is not the anchor-4 case because the when-clause is already explicit and specific with concrete trigger phrases.

Trigger Term Quality

Natural phrases users would say are present ('Go codebases', 'Go code', 'writing', 'debugging'), but common variants like 'golang', '.go files', and 'Go modules' are missing from the description itself (they only appear in metadata triggers). Good coverage with a few natural terms missing — matches the anchor-4 example.

Distinctiveness Conflict Risk

'Go codebases' / 'Go code' is a clear language-specific niche with distinct triggers and minimal overlap risk with other skills — matches the anchor-5 'clear niche with distinct triggers'.