Conciseness

The body is mostly high-value, non-obvious operational knowledge (SDK v3 gotchas, MCP preflight calls, parameter maps), but key warnings are repeated across sections — the accessKey-vs-session point appears in Common mistakes, Parameter map, the init comment, and the anonymous section, and the getLoginState/getSession warning appears three times. Long bold-heavy bullets in 'Common mistakes' could be tightened or consolidated; this fits 'mostly efficient but could be tightened' (3) rather than 4.

Actionability

The cookbook provides fully executable, copy-paste-ready snippets for every common case — init, password sign-in, anonymous (explicitly scoped demo-only), signUp + data.verifyOtp, signInWithOtp, forgot password, getSession guard, onAuthStateChange, signOut, and the auth gate — plus concrete MCP calls (queryAppAuth(action="listProviders")), env-var persistence (.env.local / import.meta.env), and console URLs. This matches the anchor 5 example of executable code covering the common cases.

Workflow Clarity

The content sequences the work explicitly (Activation Contract → provider/readiness prerequisites → parameter map → init → cookbook → Completion Bar checklist) with pre-code validation checkpoints ('Before writing any sign-in or sign-up code... call queryAppAuth(action="listProviders")'), error-recovery feedback loops (e.g. 'messageId is required' means the callback form was skipped; gateway 401 means missing session), and a final Completion Bar checklist. This matches anchor 5: clear sequence, explicit validation, feedback loops, and a checklist.

Progressive Disclosure

Good structure: clear sections, a well-signaled one-level-deep reference (references/extended-guide.md, verified to exist) with a reference index, and an appropriate split of detailed scenarios out of SKILL.md. It is not 5 because the ~230-line body still carries dense inline material (the long 'Common mistakes' list, the parameter map, the Supabase comparison) that could partly live in the reference, leaving minor organization gaps — anchor 4.

Specificity

The description names the domain ('CloudBase Web Authentication Quick Guide for frontend integration') and capability areas ('multiple login methods and complete user management'), but the actions are feature-category labels rather than concrete actions — no sign-in, registration, or session-management verbs or method names are given. It sits between anchor 2 (generic actions) and anchor 3 (1-2 concrete actions), and is not 4 because nothing as specific as 'Extract text from PDF files' is listed.

Completeness

The 'what' is clear ('Provides concise and practical Web authentication solutions with multiple login methods and complete user management'), but there is no 'Use when...' clause or equivalent trigger guidance; the phrase 'after auth-tool has already been checked' is a precondition about skill ordering, not when to activate this skill. Per the rubric guideline, a missing explicit trigger clause caps completeness at 3 — it is not 4 because the 'when' is weakly implied rather than explicit.

Trigger Term Quality

Terms like 'CloudBase', 'Web Authentication', 'login methods', 'user management', and 'frontend integration' are relevant, but common natural variations users would actually say — 'sign in', 'sign up', 'registration', 'session', '@cloudbase/js-sdk' — are missing. This matches 'some relevant keywords but missing common variations or synonyms' (3), not 4, which requires only a few natural terms absent.

Distinctiveness Conflict Risk

'CloudBase Web Authentication ... for frontend integration after auth-tool has already been checked' carves out a clear niche and explicitly scopes against the sibling auth-tool skill, keeping conflict risk low. It is not 5 because the sibling auth-tool-cloudbase skill and the generic 'Web authentication' wording leave minor overlap risk with closely related skills.