Shareable instruction files for Cursor, Claude Code, Copilot, Windsurf, and more — installed alongside your existing agent rules.
Located in `~/.claude/agents/`: | Agent | Purpose | When to Use | |-------|---------|-------------| | planner | Implementation planning | Complex features, refactoring | | architect | System design | Architectural decisions |
ALWAYS create new objects, NEVER mutate existing ones: WRONG: modify(original, field, value) → changes original in-place CORRECT: update(original, field, value) → returns new copy with change Rationale: Immutable data prevents hidden side effects, makes debugging easier, and enables safe concurrency.
Test Types (ALL required): 1. **Unit Tests** - Individual functions, utilities, components 2. **Integration Tests** - API endpoints, database operations 3. **E2E Tests** - Critical user flows (framework chosen per language)
Read [AGENTS.md](AGENTS.md) for repository work. For installation, follow [INSTALL.md](INSTALL.md): show only the target agent's supported options directly in the conversation and use its [selection procedure](INSTALL.md#choose-options), preferring native multi-select questions. Export a selection document only when requested.