Originally published at https://www.bampouris.eu/blog/react-useeffect-guide-skill/ Introduction useEffect is arguably the most misunderstood hook in the React ecosystem. Since its introduction in React 16.8, it has become the default escape hatch for everything from data fetching and subscriptions to manual DOM mutations and state synchronization. Yet, its flexibility is also its greatest liability: developers routinely reach for useEffect when a derived value, an event handler, or a simple key prop would suffice. The consequences are tangible — stale closures, missing cleanup functions, race conditions in asynchronous logic, and dependency arrays that lie about what the Effect actually needs. The React team has been explicit about this: "You Might Not Need an Effect." To operationalize this guidance within AI-assisted development workflows, I created the react-useeffect-guide skill — a portable, agent-agnostic knowledge module that any AI coding agent can load and apply.…