Summary
Claude Code is Anthropic’s coding agent CLI. Its power comes from combining features into workflows, not using them individually. The feature set maps directly to harness engineering concepts: Memory/CLAUDE.md = feedforward guides, Hooks/Tests = feedback sensors.
Key Points
- 10 core features: Slash Commands, Memory, Skills, Subagents, MCP, Hooks, Plugins, Checkpoints, Advanced Features (planning/thinking), CLI
- The real leverage is composition: e.g., code review = Slash Commands + Subagents + Memory + MCP
- Harness engineering mapping:
- CLAUDE.md / Memory = feedforward (guides agent before acting)
- Hooks / Tests = feedback (sensors after action)
- Skills = reusable harness components
- Checkpoints = rollback capability (safe experimentation)
- Feature persistence spectrum: Session-only (slash commands) → Cross-session (memory) → Real-time (MCP)
- Learning path: 11-13 hours total, but 15 min for immediate value
Feature Quick Reference
| Feature | Invocation | Persistence | Harness Role |
|---|---|---|---|
| Memory/CLAUDE.md | Auto-loaded | Cross-session | Feedforward guide |
| Skills | Auto-invoked | Filesystem | Reusable harness |
| Hooks | Event-triggered | Configured | Feedback sensor |
| Subagents | Auto-delegated | Isolated | Task decomposition |
| MCP | Auto-queried | Real-time | External data access |
| Checkpoints | Manual/Auto | Session | Rollback safety net |
Open Questions
- What’s the optimal CLAUDE.md structure for different project types?
- How to version-control and share Claude Code configurations across teams?
- Best practices for hook complexity vs. maintainability?
Evidence Timeline
- 2026-04-07: Compiled from claude-howto guide (5,900+ stars, luongnv89)