sub-agents

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

1. Single responsibility - One clear purpose per agent
2. Restrict tools - Only grant what's needed
3. Clear descriptions - Action-oriented, include "proactively"
4. Version control - Check .claude/agents/ into git