Mostly efficient — tables of concrete fixes with detailed material offloaded to references — but there is redundancy across the Quick Reference, Common Mistakes, and Security Anti-Patterns tables (e.g. SQL injection and hardcoded secrets recur), and STRIDE/DREAD are explained inline before being pointed to. Not 3 because it could be tightened by deduplicating overlapping tables; not 1 because it assumes Claude's competence and avoids padding with basics.

Provides specific, executable solutions per vulnerability — 'database/sql with ? placeholders', 'exec.Command with separate args', 'os.Root', 'crypto/subtle.ConstantTimeCompare' — plus runnable commands like 'go tool gosec ./...', 'go tool govulncheck ./...', 'go test -race ./...', 'go test -fuzz=Fuzz'. Not below 3 because guidance is concrete and copy-paste ready rather than abstract.

Modes (Review/Audit/Coding) and the four-step 'Research Before Reporting' are clearly sequenced, with verification tooling (gosec, govulncheck, -race, fuzz) present. Capped at 2 because the batch Audit workflow — the most destructive/large-scale operation — lacks an explicit validate-fix-retry feedback loop for findings (it aggregates and reports, with no 're-verify the fix' checkpoint), which the rubric penalizes for batch operations.

The body is a concise overview pointing to 12 one-level-deep reference files, each clearly signaled with a named link and one-line description; all referenced paths (cryptography.md, injection.md, filesystem.md, network.md, cookies.md, third-party.md, memory-safety.md, secrets.md, logging.md, threat-modeling.md, architecture.md, checklist.md) exist in ./references/. Not below 3 because navigation is explicit and content is appropriately split.

Lists multiple concrete capabilities and domains — 'injection (SQL, command, XSS), cryptography, filesystem safety, network security, cookies, secrets management, memory safety, and logging' alongside 'writing, reviewing, or auditing Go code' — rather than vague abstractions. Not below 3 because it enumerates specific actions and domains; not above because the scale caps at 3.

Explicitly answers both what ('Security best practices and vulnerability prevention for Golang. Covers...') and when ('Apply when writing, reviewing, or auditing Go code for security, or when working on any risky code involving...'). The explicit 'Apply when' trigger clause satisfies the completeness anchor 3.

Natural user-facing terms are well covered: 'writing, reviewing, or auditing Go code for security', 'risky code involving crypto, I/O, secrets management, user input handling, or authentication', 'Golang'. These are phrases a user would naturally say; not below 3 since coverage spans common variations.

A clear niche — Go security engineering — with distinct, domain-specific triggers that are unlikely to conflict with general-purpose skills. Not below 3 because the scope (Golang + security) is well bounded and specific.