Conciseness

The body is efficient and assumes Claude's competence — dense tables, tight code blocks, no concept over-explanation — matching the 4 anchor. It falls short of the 5 anchor because of minor time-sensitive detail (the pinned version "docker.io/cloudflare/sandbox:0.7.0") placed outside any 'old patterns'/deprecated section, which the guidelines penalize.

Actionability

Guidance is fully executable and copy-paste ready: install commands with a required check ("npm install @cloudflare/sandbox", "docker info"), the exact wrangler.jsonc block, the required "export { Sandbox }" entry snippet, and concrete API examples (exec, runCode with context reuse, file operations, exposePort) covering the common cases. This matches the 5 anchor.

Workflow Clarity

The sequence is clearly ordered (verify installation first, configure wrangler, export Sandbox, use the API, destroy for cleanup) and begins with an explicit validation checkpoint ("FIRST: Verify Installation" with docker info), plus cleanup guidance in the lifecycle and anti-patterns sections. It misses the 5 anchor because there is no explicit post-deploy/runtime verification step or error-recovery loop for the multi-step setup.

Progressive Disclosure

The body is a clear overview with common cases inline (Quick Reference table, core patterns) and the bulk detail correctly split into two well-signaled, one-level-deep references (references/api-quick-ref.md, references/examples.md), both of which exist and contain substantive content. This matches the 5 anchor; there is no nesting or buried reference.

Specificity

The description lists several specific capability areas ("Sandbox SDK lifecycle, commands, files, code interpreter, and preview URLs") grounded in a concrete domain ("Build sandboxed applications for secure code execution"). It falls short of the 5 anchor because these are topical nouns rather than the multiple concrete verb-actions (e.g., "extract text, fill forms, merge documents") of a comprehensive listing, and ahead of 3 because coverage goes well beyond 1-2 actions.

Completeness

It explicitly answers both questions with concrete trigger phrases: the "what" via "Build sandboxed applications for secure code execution" plus the coverage list, and the "when" via the explicit "Load when building AI code execution, code interpreters, CI/CD systems, interactive dev environments, or executing untrusted code" clause. This matches the 5 anchor exactly; the 4 anchor applies only when the 'when' is less explicit.

Trigger Term Quality

Trigger terms are natural phrases users would say: "AI code execution, code interpreters, CI/CD systems, interactive dev environments, or executing untrusted code". A few natural synonyms/variations are missing (e.g., "run arbitrary code", "sandbox environment", file extensions), which keeps it below the comprehensive 5 anchor but clearly above the 3 anchor's partial coverage.

Distinctiveness Conflict Risk

The sandboxed-code-execution niche is mostly distinct, but "CI/CD systems" and "interactive dev environments" are broad enough that users building general CI/CD or dev-tooling projects could trigger this skill incorrectly, and the identifying vendor ("Cloudflare") appears only indirectly at the end. Minor overlap risk with closely related skills matches the 4 anchor rather than the minimal-conflict 5 anchor.