sub-agents

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