Claude
Skills
Sign in
Back

subagents-reference

Included with Lifetime
$97 forever

Claude Code subagents configuration reference. Use when creating custom subagents, understanding agent types, configuring agent prompts, or extending the Task tool with specialized agents.

AI Agents

What this skill does


# Claude Code Subagents Reference

Subagents are specialized AI assistants that Claude can spawn for specific tasks. Define custom agents to extend Claude's capabilities.

## Agent File Locations

```
~/.claude/agents/              # User agents (all projects)
.claude/agents/                # Project agents (team shared)
```

## Agent File Format

```markdown
---
name: agent-identifier
description: What this agent does and when to use it
model: sonnet
tools:
  - Read
  - Grep
  - Glob
  - Bash
---

# Agent Name

Detailed instructions for the agent's behavior.

## Capabilities
- Specific task the agent handles
- Another capability

## Approach
How the agent should tackle problems.
```

## Frontmatter Fields

| Field | Required | Type | Description |
|-------|----------|------|-------------|
| `name` | No | string | Agent identifier for Task tool |
| `description` | Yes | string | When/why to use this agent |
| `model` | No | string | haiku, sonnet, opus |
| `tools` | No | array | Available tools |
| `allowed_tools` | No | array | Alias for `tools` |

## Built-in Agent Types

| Agent | Purpose | Tools |
|-------|---------|-------|
| `Explore` | Codebase exploration | Read, Grep, Glob |
| `general-purpose` | Multi-step tasks | All tools |
| `Bash` | Command execution | Bash |
| `Plan` | Implementation planning | All tools |

## Custom Agent Example

```markdown
---
name: security-reviewer
description: Review code for security vulnerabilities. Use when checking for injection, XSS, auth issues.
model: sonnet
tools:
  - Read
  - Grep
  - Glob
---

# Security Review Agent

You are a security specialist reviewing code for vulnerabilities.

## Review Checklist
1. SQL injection
2. XSS vulnerabilities
3. Authentication bypass
4. Sensitive data exposure
5. Insecure dependencies

## Process
1. Read the target files
2. Search for common vulnerability patterns
3. Report findings with severity ratings
```

## Invoking Agents

### Via Task Tool
```
Claude uses Task tool with:
- subagent_type: "security-reviewer"
- prompt: "Review the auth module for vulnerabilities"
```

### From Skills/Instructions
Reference agent in CLAUDE.md or skills:
```
When reviewing security, use the security-reviewer agent.
```

## Tool Restrictions

Limit what agents can do:

```yaml
tools:
  - Read      # Read files
  - Grep      # Search content
  - Glob      # Find files
  # No Bash, Write, Edit = read-only agent
```

## Model Selection

| Model | Use Case |
|-------|----------|
| `haiku` | Fast, simple tasks |
| `sonnet` | Balanced (default) |
| `opus` | Complex reasoning |

## Agent Prompt Best Practices

1. **Clear identity**: State what the agent specializes in
2. **Specific instructions**: Be explicit about approach
3. **Tool guidance**: Explain which tools to use when
4. **Output format**: Specify expected output structure
5. **Boundaries**: Define what's in/out of scope

## Example: Code Reviewer

```markdown
---
name: code-reviewer
description: Review code changes for quality, patterns, and issues
model: sonnet
tools:
  - Read
  - Grep
  - Glob
---

# Code Review Agent

Review code for:
- Logic errors
- Performance issues
- Code style violations
- Missing error handling

## Output Format
For each issue found:
1. File and line number
2. Issue description
3. Severity (high/medium/low)
4. Suggested fix
```

## Example: Test Writer

```markdown
---
name: test-writer
description: Write unit tests for functions and modules
model: sonnet
tools:
  - Read
  - Write
  - Bash
---

# Test Writing Agent

Write comprehensive unit tests.

## Approach
1. Read the target code
2. Identify testable functions
3. Write test cases covering:
   - Happy path
   - Edge cases
   - Error conditions
4. Run tests to verify
```

## Agent Communication

Agents receive:
- The prompt from Task tool
- Access to specified tools
- Project context

Agents return:
- Single response to parent Claude
- Any artifacts created

## Debugging

```bash
# List available agents
/agents

# Check agent loading
claude --debug
```

---

For complete documentation, see:
- [subagents-full.md](subagents-full.md) - Complete subagents reference

Related in AI Agents