The body is lean and assumes Claude's competence — it skips tutorial fluff and leads with a use-case table and executable code; not level 2 because the single analogy line ('Kind of like useEffect() for the central data store') is high-signal context rather than unnecessary padding.

Provides fully executable TS/TSX examples (TimeManager, LoggingManager, CustomSubsManager, DataProvider wiring) plus concrete API method lists (ctrl.fetch, ctrl.expireAll, ctrl.set) and a scenario-to-technique table; not level 2 because the code is copy-paste ready rather than pseudocode.

As a capability/reference skill it cleanly sequences scenarios via the use-case table mapping each task to its technique and reference file; per scoring_notes a clear, well-organized reference skill scores 3, and there are no destructive/batch ops that would require validation checkpoints.

SKILL.md is a clear overview with a References section listing one-level-deep, real files (Manager, Actions, Controller, LogoutManager, getDefaultManagers, managers — verified present) and a use-case table signaling which reference to consult per scenario; not level 2 because references are clearly signaled and appropriately split.

Enumerates many concrete capabilities ('websocket, SSE, polling, real-time updates, subscriptions, logging, analytics, metrics/timing, error reporting (Sentry), toast notifications') in third person, matching the 'lists multiple specific concrete actions' anchor; not level 2 because coverage is comprehensive rather than partial.

Explicitly states both what it does ('Implement @data-client Managers for global/background side effects') and when to use it ('Use when adding cross-cutting store behavior, reacting to dispatched actions, or handling external event streams.'); not level 2 because the 'Use when' trigger is explicit rather than implied.

Includes natural terms users would say — 'websocket', 'polling', 'real-time updates', 'toast notifications', 'refetch on window focus', 'cross-tab sync', 'offline persistence', 'auth logout on 401' — giving good coverage; not level 2 because common variations are present, not just one or two keywords.

Anchored to the specific '@data-client' library with distinctive triggers like 'BroadcastChannel', 'redux-style action handling', and 'DataProvider managers prop', giving a clear niche unlikely to fire for the wrong skill; not level 2 because the specialization sharply limits overlap.