SKILL.md
Sub-Agents Reference
Create specialized AI agents with isolated contexts for specific tasks.
When to Use
- "How do I create a sub-agent?"
- "Configure agent tools"
- "What built-in agents exist?"
- "Agent model selection"
- "Agent chaining patterns"
Quick Start
Interactive (Recommended)
/agents
Opens menu to create, edit, and manage agents.
Manual Creation
mkdir -p .claude/agents
cat > .claude/agents/reviewer.md << 'EOF'
---
name: reviewer
description: Code review specialist. Use proactively after code changes.
tools: Read, Grep, Glob, Bash
model: sonnet
---
You are a senior code reviewer focusing on quality and security.
## Review Checklist
- Code clarity and naming
- Error handling
- Security vulnerabilities
- Test coverage
EOF
CLI-Based
claude --agents '{
"reviewer": {
"description": "Code reviewer",
"prompt": "Review for quality and security",
"tools": ["Read", "Bash"],
"model": "sonnet"
}
}'
Agent File Format
---
name: agent-name
description: When/why to use this agent
tools: Read, Edit, Bash # Optional, inherits all if omitted
model: sonnet # sonnet, haiku, claude-opus-4-5-20251101, inherit
---
System prompt content here...
Configuration Fields
Field
Required
Options
name
Yes
lowercase, hyphens
description
Yes
When to use
tools
No
Tool list (inherits all if omitted)
model
No
sonnet, haiku, claude-opus-4-5-20251101, inherit
Built-In Agents
Agent
Model
Tools
Purpose
General-purpose
Sonnet
All
Complex multi-step tasks
Plan
Sonnet
Read-only
Plan mode research
Explore
Haiku
Read-only
Fast codebase search
Model Selection
Model
Speed
Best For
Haiku
Fastest
Search, quick lookups
Sonnet
Fast
Most tasks (default)
Opus
Slower
Complex reasoning
Tool Combinations
# Code Reviewer (read-only)
tools: Read, Grep, Glob, Bash
# Debugger
tools: Read, Edit, Bash, Grep, Glob
# Implementer
tools: Read, Write, Edit, Bash, Glob
Example Agents
Code Reviewer
---
name: code-reviewer
description: Reviews code for quality and security. Use after code changes.
tools: Read, Grep, Glob, Bash
model: sonnet
---
Review code for:
- Security vulnerabilities
- Code quality issues
- Missing error handling
- Test coverage gaps
Output findings by priority: Critical > Warning > Suggestion
Debugger
---
name: debugger
description: Debug errors and test failures.
tools: Read, Edit, Bash, Grep, Glob
model: inherit
---
Debugging process:
1. Capture error details
2. Identify failure location
3. Form hypotheses
4. Test and verify
5. Implement fix
File Locations
Type
Location
Priority
Project
.claude/agents/
Highest
User
~/.claude/agents/
Lower
Advanced Patterns
Resumable Agents
[Agent returns agentId: "abc123"]
# Later: resume with context
claude -r "abc123" "Continue analysis"
Agent Chaining
Use code-analyzer to find issues,
then use optimizer to fix them
Best Practices
- Single responsibility - One clear purpose per agent
- Restrict tools - Only grant what's needed
- Clear descriptions - Action-oriented, include "proactively"
- Version control - Check
.claude/agents/into git