Agent Creator Skill for Claude

Agent Creator

Overview

Creates subagent definitions for Claude Code. Subagents are specialized assistants

that Claude can invoke for specific tasks.

When to use: User requests an agent, wants to add specialized subagent to plugin, or needs agent structure guidance.

References: Consult

plugins/meta/claude-docs/skills/official-docs/reference/plugins-reference.md and

plugins/meta/claude-docs/skills/official-docs/reference/sub-agents.md for specifications.

CRITICAL: Two Types of Agents

Claude Code has two distinct agent types with different requirements:

Plugin Agents (plugins/*/agents/)

Purpose: Agents distributed via plugins for team/community use

Required frontmatter fields:

• description (required) - What this agent specializes in
• capabilities (required) - Array of specific capabilities

Location: plugins/<category>/<plugin-name>/agents/agent-name.md

Example:

---
description: Expert code reviewer validating security and quality
capabilities: ["vulnerability detection", "code quality review", "best practices"]
---

User/Project Agents (.claude/agents/)

Purpose: Personal agents for individual workflows

Required frontmatter fields:

• name (required) - Agent identifier
• description (required) - When to invoke this agent
• tools (optional) - Comma-separated tool list
• model (optional) - Model alias (sonnet, opus, haiku)

Location: .claude/agents/agent-name.md or ~/.claude/agents/agent-name.md

Example:

---
name: code-reviewer
description: Expert code review. Use after code changes.
tools: Read, Grep, Glob, Bash
model: sonnet
---

Key difference: User agents have name field and system prompt. Plugin agents have capabilities array and documentation.

Agent Structure Requirements (Plugin Agents)

Every plugin agent MUST include:

• Frontmatter with description and capabilities array
• Agent title as h1
• Capabilities section explaining what agent does
• When to Use section with invocation criteria
• Context and Examples with concrete scenarios
• Located in agents/agent-name.md within plugin

Creation Process

Step 0: Determine Agent Type

Ask the user:

• Is this for a plugin (team/community distribution)?
• Or for personal use (.claude/agents/)?

If personal use: Use user agent format with name, description, system prompt. See plugins/meta/claude-docs/skills/official-docs/reference/sub-agents.md for examples.

If plugin: Continue with plugin agent format below.

Step 1: Define Agent Purpose

Ask the user:

• What specialized task does this agent handle?
• What capabilities distinguish it from other agents?
• When should Claude invoke this vs doing work directly?

Step 2: Determine Agent Name

Create descriptive kebab-case name:

• "security review" → security-reviewer
• "performance testing" → performance-tester
• "API documentation" → api-documenter

Step 3: List Capabilities

Identify 3-5 specific capabilities:

• Concrete actions the agent performs
• Specialized knowledge it applies
• Outputs it generates

Step 4: Structure the Agent

Use this template:

---
description: One-line agent description
capabilities: ["capability-1", "capability-2", "capability-3"]
---

# Agent Name

Detailed description of agent's role and expertise.

## Capabilities

- **Capability 1**: What this enables
- **Capability 2**: What this enables
- **Capability 3**: What this enables

## When to Use This Agent

Claude should invoke when:
- Specific condition 1
- Specific condition 2
- Specific condition 3

## Context and Examples

**Example 1: Scenario Name**

User requests: "Help with X"
Agent provides: Specific assistance using capabilities

**Example 2: Another Scenario**

When Y happens, agent does Z.

Step 5: Verify Against Official Docs

For plugin agents:

Check plugins/meta/claude-docs/skills/official-docs/reference/plugins-reference.md (requires capabilities array).

For user agents:

Check plugins/meta/claude-docs/skills/official-docs/reference/sub-agents.md (requires name field).

Key Principles

• Specialization: Agents should have focused expertise
• Clear Invocation: Claude must know when to use this agent
• Concrete Capabilities: List specific things agent can do
• Examples: Show real scenarios where agent helps

Examples

Example 1: Security Reviewer Agent

User: "Create an agent for security reviews"

Process:

• Purpose: Reviews code for security vulnerabilities
• Name: security-reviewer
• Capabilities: ["vulnerability detection", "security best practices", "threat modeling"]
• Structure: Include when to invoke, examples of security issues
• Create: agents/security-reviewer.md

Output: Agent that Claude invokes for security-related code review

Example 2: Performance Tester Agent

User: "I need an agent for performance testing"

Process:

• Purpose: Designs and analyzes performance tests
• Name: performance-tester
• Capabilities: ["load testing", "benchmark design", "performance analysis"]
• Structure: When to use for optimization vs testing
• Create: agents/performance-tester.md

Output: Agent that Claude invokes for performance concerns