Conciseness

The body is dense with non-obvious, high-value gotchas (bare boolean flags, 'fastly domain create' 403 path, '--version active', KV eventual consistency, SHIELD vs CODE column) and assumes Claude's competence throughout. However, the opening 'Trigger and scope' section re-states coverage the frontmatter description already declares, and the Troubleshooting section recap re-points to sections already covered inline, so a few tokens could be trimmed — anchor 4 ('minor instances of over-explanation that could be trimmed') fits better than 5.

Actionability

Fully executable, copy-paste-ready bash for the common cases (autoclone backend/domain creation, stats historical/realtime, full pre-flight curl/openssl checks) plus explicit CORRECT/WRONG flag contrasts. This matches anchor 5 ('copy-paste ready code or commands; specific examples cover the common cases'); anchor 4's 'minor gaps' is not in evidence.

Workflow Clarity

The New VCL Service Setup Workflow is a clearly numbered sequence with explicit validation checkpoints (pre-flight origin/cert check, 'validate version before activating', post-activation curl verification) and feedback loops for error recovery ('If 500 Domain Not Found, wait and retry... If 503, check backend SSL settings'), plus propagation-delay retry guidance. This matches anchor 5; it is not anchor 4 because checkpoints and error-recovery loops are both present and explicit.

Progressive Disclosure

The body is a genuine overview that keeps only high-frequency gotchas inline and delegates bulk detail via a references table with 'Use when...' guidance pointing to nine real, one-level-deep files (all verified to exist in references/). Matches anchor 5 ('clear overview with well-signaled one-level-deep references'); there is no inlining of content that belongs in a separate file.

Specificity

The description lists many concrete, specific actions ('purging cache, configuring log streaming, setting up TLS certificates, managing KV/config/secret stores, checking service stats, authenticating with Fastly SSO') with comprehensive coverage of the CLI's surface, in third-person voice. It matches the score-5 anchor ('lists multiple specific concrete actions; comprehensive coverage') and exceeds anchor 4, which expects only 'several specific actions with minor gaps'.

Completeness

It explicitly answers both questions: the 'what' ('Executes Fastly CLI commands for managing CDN services, Compute deploys, and edge infrastructure') and an explicit 'Use when...' clause enumerating concrete trigger scenarios. This mirrors the score-5 reference example structure; anchor 4 ('when could be more explicit or specific') does not fit since the when-clause is highly specific.

Trigger Term Quality

It combines natural user phrasing ('running fastly CLI commands', 'purging cache', 'deploying Fastly Compute applications', 'working with fastly.toml') with literal command triggers ('fastly service', 'fastly compute', 'fastly auth', or any Fastly CLI subcommand'). This is comprehensive natural-term coverage including synonyms and exact CLI tokens, matching anchor 5 rather than anchor 4's 'a few natural terms missing'.

Distinctiveness Conflict Risk

It occupies a clear niche: everything is Fastly-specific (fastly.toml, Fastly SSO, Fastly service IDs, autocloning, named subcommands), so it is unlikely to trigger for a non-Fastly skill. Minimal conflict risk matches anchor 5; anchor 4 ('minor overlap risk with closely related skills') would require some ambiguity that is not present.