This skill should be used when the user asks to "create an agent", "add an agent", "write a subagent", "agent frontmatter", "when to use description", "agent examples", "agent tools", "agent colors", "autonomous agent", or needs guidance on agent structure, system prompts, triggering conditions, or agent development best practices for Claude Code plugins.
View on GitHubfcakyon/claude-codex-settings
plugin-dev
January 15, 2026
Select agents to install to:
npx add-skill https://github.com/fcakyon/claude-codex-settings/blob/main/plugins/plugin-dev/skills/agent-development/SKILL.md -a claude-code --skill agent-developmentInstallation paths:
.claude/skills/agent-development/# Agent Development for Claude Code Plugins
## Overview
Agents are autonomous subprocesses that handle complex, multi-step tasks independently. Understanding agent structure, triggering conditions, and system prompt design enables creating powerful autonomous capabilities.
**Key concepts:**
- Agents are FOR autonomous work, commands are FOR user-initiated actions
- Markdown file format with YAML frontmatter
- Triggering via description field with examples
- System prompt defines agent behavior
- Model and color customization
## Agent File Structure
### Complete Format
```markdown
---
name: agent-identifier
description: Use this agent when [triggering conditions]. Examples:
<example>
Context: [Situation description]
user: "[User request]"
assistant: "[How assistant should respond and use this agent]"
<commentary>
[Why this agent should be triggered]
</commentary>
</example>
<example>
[Additional example...]
</example>
model: inherit
color: blue
tools: ["Read", "Write", "Grep"]
---
You are [agent role description]...
**Your Core Responsibilities:**
1. [Responsibility 1]
2. [Responsibility 2]
**Analysis Process:**
[Step-by-step workflow]
**Output Format:**
[What to return]
```
## Frontmatter Fields
### name (required)
Agent identifier used for namespacing and invocation.
**Format:** lowercase, numbers, hyphens only
**Length:** 3-50 characters
**Pattern:** Must start and end with alphanumeric
**Good examples:**
- `code-reviewer`
- `test-generator`
- `api-docs-writer`
- `security-analyzer`
**Bad examples:**
- `helper` (too generic)
- `-agent-` (starts/ends with hyphen)
- `my_agent` (underscores not allowed)
- `ag` (too short, < 3 chars)
### description (required)
Defines when Claude should trigger this agent. **This is the most critical field.**
**Must include:**
1. Triggering conditions ("Use this agent when...")
2. Multiple `<example>` blocks showing usage
3. Context, user request, and assistant response in each example
4. `<commentary>` explainin