Conciseness

The body earns most of its tokens on genuinely non-obvious v3 SDK gotchas (verifyOtp callback vs standalone, misleading getLoginState uid, gateway 401 without session) rather than explaining concepts Claude already knows — but the same 4-5 warnings are each restated 2-4 times across 'Common mistakes', the parameter map, the init snippet, and the cookbook (e.g. the accessKey/session warning appears at lines 49, 100, 116-119). This fits 'mostly efficient but could be tightened' rather than 2, since the padding is duplication of valuable content, not known-concept filler.

Actionability

The cookbook provides copy-paste-ready executable snippets for every common case (init with accessKey, signInWithPassword, signUp + data.verifyOtp, signInWithOtp, resetPasswordForEmail/updateUser, getSession guard, onAuthStateChange, signOut), plus exact MCP calls with parameters (queryAppAuth(action="listProviders"), manageAppAuth(action="patchLoginStrategy", patch={usernamePassword: true})). Fully executable guidance covering the common cases.

Workflow Clarity

A clear sequenced flow with explicit validation checkpoints: verify provider 'On: "TRUE"' via queryAppAuth before writing sign-in code, check SMTP before email signUp, resolve env aliases via queryEnv, persist the publishable key to .env.local, error-recovery fallback console links when MCP fails, and a final Completion Bar checklist gating task completion. This matches the anchor-5 pattern of sequence + validation + error feedback loops.

Progressive Disclosure

Good structure: the main API cookbook lives in SKILL.md while detailed per-method scenarios are delegated to references/extended-guide.md (which exists in the bundle), signaled from a dedicated 'Extended guide' section, one level deep. It stays at 4 rather than 5 because the gotchas list is long enough to be inline material that arguably belongs in the reference, and the same reference link is repeated three times (gotchas, Extended guide, Reference index).

Specificity

It names the domain ("CloudBase Web Authentication Quick Guide for frontend integration") and gestures at 1-2 actions ("multiple login methods", "complete user management"), but no concrete named operations (no signInWithPassword, OTP, session handling, or SDK names). This matches 'names domain and 1-2 concrete actions' rather than score 4, which requires several specific actions, and is above score 2 because the actions are not purely generic.

Completeness

The 'what' is present ("Provides concise and practical Web authentication solutions with multiple login methods and complete user management") but the only 'when' is an ordering precondition ("after auth-tool has already been checked"), not an explicit trigger clause. Per the guideline that a missing 'Use when...' or equivalent explicit trigger guidance caps completeness at 3, this cannot score 4.

Trigger Term Quality

Relevant keywords are present ("CloudBase", "Web Authentication", "login methods", "frontend integration", "user management") but common natural variations users would actually say are missing: "sign in", "sign up", "register", "session", "@cloudbase/js-sdk". This fits 'some relevant keywords but missing common variations or synonyms' — not score 4, whose bar is good coverage with only a few terms missing.

Distinctiveness Conflict Risk

The description carves a fairly clear niche (CloudBase Web frontend auth sequenced after auth-tool), with low overlap risk against unrelated skills. It stays at 4 rather than 5 because it does not state its own negative boundaries (mini-program/native/server auth live in the body, not the description), leaving minor overlap risk with the sibling auth-tool-cloudbase skill.