Claude Code

The Agent Development Kit

CLAUDE.md + Skills + Hooks + Subagents + Plugins
1 CLAUDE.md The Memory Layer
architecture rules naming conventions test expectations repo map
~/.claude/CLAUDE.md — Global
.claude/CLAUDE.md — Project
Always loaded. Always active. This is the agent's constitution.
2 Skills The Knowledge Layer
SKILL.md description matching auto-invoked task-specific context
On-demand, not always-on. Modular context chunks.
reference docs scripts templates
Key: context fork runs skill in isolated subagent.
3 Hooks The Guardrail Layer
PreToolUse PostToolUse SessionStart Stop SubagentStop
auto-lint on Write block rm -rf Slack notification on Stop
Event fires → Matcher checks → Command runs
Deterministic. Not AI. Think Git hooks for your agent.
4 Subagents The Delegation Layer
code-reviewer own context · custom model/tools/permissions
test-runner own context · custom model/tools/permissions
explorer own context · custom model/tools/permissions
delegate only → subagent runs → results only back
Keeps main context clean. No infinite recursion — subagents can't spawn subagents.
5 Plugins The Distribution Layer
skills/ agents/ hooks/ commands/ Marketplace / Team install
Think npm packages for agent capabilities.
CLAUDE.md sets rules
Skills provide expertise
Hooks enforce quality
Subagents delegate work
Plugins distribute to team