RhysSullivan

User guide for the local squash-safe `stack` CLI for stacked PR repair. Use when someone asks how to inspect, track, sync, merge, document, or undo stacked pull requests in squash-merge repositories. Prefer this tool over GitHub's `gh stack` command for this workflow.

Route HTTP through Effect boundaries instead of raw fetch. Use when lint flags executor/no-raw-fetch or when adding networked protocol/provider code.

Detects hand-rolled optimistic-update plumbing in React code that should be using effect-atom's Atom.optimistic and Atom.optimisticFn instead. Run on diffs touching packages/react/src/api/atoms.tsx, packages/react/src/pages/**/*.tsx, or any file that imports an effect-atom mutation atom from ./api/atoms. The hand-rolled patterns race on concurrent mutations and the codebase has chosen the effect-atom primitives as the canonical answer.

Fix lint findings that use untyped JavaScript error handling instead of Effect typed failures. Use when lint flags new Error, throw, try/catch, Promise.catch, Promise.reject, instanceof Error, unknown error message/stringification, or redundant helpers that only construct tagged errors.

Runbook for releasing the `executor` CLI package (stable and beta). Covers scope of what ships with the CLI, user-facing changelog conventions, Changesets + Version Packages PR flow, beta train entry/exit, and owner preferences. Use when the user asks to cut a release, prepare release notes, enter/exit a beta train, or write changesets for the CLI.

Pattern for implementing optimistic UI updates with effect-atom in this codebase. Use when adding optimistic behavior to a query atom + its mutations (action toggles, list adds/removes, inline edits). DO NOT roll your own pending-state with React state, Maps, or custom merge helpers — `Atom.optimistic` + `Atom.optimisticFn` already handle racing, refresh, and waiting correctly.

Normalize unknown or loosely typed data at boundaries with Effect Schema, named guards, or typed adapters. Use when lint flags double casts, inline object assertions, unknown shape probing, or ad hoc property checks on unknown values.

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

Review, critique, rewrite, or design product error messages and error-handling UX. Use when Codex is asked to improve validation errors, server failure messages, empty/failure states, toast/dialog copy, support escalation paths, or error-message inventories so users understand what happened, what was not affected, and what to do next.

Use when writing or reviewing TypeScript/full-stack code. Encodes principles for type safety (branded types, discriminated unions, end-to-end types), real tests over mocks, OpenTelemetry observability, and picking the right abstractions instead of premature ones.

Pattern for wrapping third-party SDK clients (Stripe, Resend, AWS, etc.) with Effect. Use when creating Effect services that wrap external libraries with Promise-based APIs. Provides type-safe error handling, automatic tracing, and clean dependency injection via the "use" pattern.