# Wrdn Effect Atom Reactivity Keys

> Add reactivityKeys to effect-atom write mutation calls. Use when lint flags a useAtomSet mutation call that mutates data without invalidation keys.

- Skill: `usefulsoftwareco/wrdn-effect-atom-reactivity-keys` (Agent Skill)
- Install (CLI): `npx skillmds@latest add usefulsoftwareco/wrdn-effect-atom-reactivity-keys`
- Raw SKILL.md: https://api.skillmd.com/api/skills/usefulsoftwareco/wrdn-effect-atom-reactivity-keys/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: usefulsoftwareco (https://skillmd.com/u/usefulsoftwareco)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/usefulsoftwareco/wrdn-effect-atom-reactivity-keys

---


Effect-atom write mutations must say which reads they invalidate.

## Fix Shape

- Find the `useAtomSet(...)` write mutation call.
- Add `reactivityKeys` to the mutation payload at the call site.
- Use the narrowest keys that cover the rows/lists affected by the write.
- Keep read-only probe/preview OAuth flows out of this pattern.
- If the mutation should update UI immediately, check whether `wrdn-effect-atom-optimistic` also applies.

## Good

```ts
await updateSource({
  params: { scopeId, sourceId },
  payload,
  reactivityKeys: [["sources", scopeId]],
});
```