fix(agent-development): optimize description for capacity and clarity (#27)

## Description

Optimizes the agent-development skill description to improve capacity
headroom and follow documentation best practices.

## Type of Change

- [ ] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update (improvements to README, CLAUDE.md, or
component docs)
- [x] Refactoring (code change that neither fixes a bug nor adds a
feature)
- [ ] Configuration change (changes to .markdownlint.json, plugin.json,
etc.)

## Component(s) Affected

- [ ] Commands (`/plugin-dev:*`)
- [x] Skills (methodology and best practices)
- [ ] Agents (requirements-assistant)
- [ ] Hooks (UserPromptSubmit)
- [ ] Documentation (README.md, CLAUDE.md, SECURITY.md)
- [ ] Configuration (.markdownlint.json, plugin.json, marketplace.json)
- [ ] Issue/PR templates
- [ ] Other (please specify):

## Motivation and Context

The agent-development skill description needed optimization per issue
recommendations:

1. **Added "what it provides" clause** - Description was ~90% trigger
phrases, now starts with purpose
2. **Condensed redundant trigger phrases** - Reduced from 579 → 424
characters (27% reduction)
3. **Removed duplicate suffix** - "for Claude Code plugins" appeared at
both start and end
4. **Improved structure** - Follows docs recommendation: "description
should include both what the Skill does AND when to use it"

**Result**: 600 characters of headroom for future trigger phrase
additions.

Fixes #23

## How Has This Been Tested?

**Test Configuration**:
- OS: macOS Darwin 25.1.0
- Testing method: Character count verification

**Test Steps**:
1. Verified original description: 579 characters
2. Applied optimizations per issue recommendations
3. Verified new description: 424 characters (✅ under 900 target)
4. Ran `markdownlint` - no errors

## Checklist

### General

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings or errors

### Documentation

- [x] I have updated YAML frontmatter (if applicable)

### Markdown

- [x] I have run `markdownlint` and fixed all issues

### Component-Specific Checks

#### Skills (if applicable)

- [x] Description uses third-person with specific trigger phrases
- [x] SKILL.md is under 2,000 words (progressive disclosure)

### Testing

- [x] I have tested the plugin locally

## Additional Notes

**Before (579 chars)**:
```
This skill should be used when the user asks to "create an agent", "add an agent", "write a subagent", "design an agent for [task]", "how do I write agent descriptions", "what are the agent frontmatter fields", "validate my agent", "test agent triggering", "how to restrict agent tools", "what colors can agents use", "autonomous agent", "difference between agent and skill", "agent vs command", "when should I use an agent", "agent schema", or needs guidance on agent structure, system prompts, triggering conditions, or agent development best practices for Claude Code plugins.
```

**After (424 chars)**:
```
This skill provides comprehensive agent development guidance for Claude Code plugins. Use when the user asks to "create an agent", "add an agent", "write a subagent", "agent frontmatter", "validate my agent", "test agent triggering", "agent tools", "agent colors", "autonomous agent", "agent vs skill", "agent vs command", "when to use agents", or needs guidance on agent structure, system prompts, or triggering conditions.
```

---
🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: sjnims

CLAUDE.md

@@ -6,6 +6,10 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 This repository is a **plugin marketplace** containing the **plugin-dev** plugin - a comprehensive toolkit for developing Claude Code plugins. It provides 7 specialized skills, 3 agents, and 1 guided workflow command for building high-quality plugins.
 
+## Quick Reference
+
+**Current Version**: v0.1.0
+
 ## Repository Structure
 
 ```
@@ -22,6 +26,15 @@ plugin-dev/                      # Marketplace root
 └── .github/workflows/           # CI/CD workflows
 ```
 
+## Architecture Note
+
+This repo has two levels of `.claude-plugin/`:
+
+- **Root level**: `/.claude-plugin/marketplace.json` - Marketplace manifest listing available plugins
+- **Plugin level**: `/plugins/plugin-dev/.claude-plugin/plugin.json` - Individual plugin manifest
+
+When testing locally, point to the plugin directory, not the root.
+
 ## Key Conventions
 
 ### Skill Structure
@@ -154,3 +167,7 @@ Key workflows in `.github/workflows/`:
 - `component-validation.yml` - Validates plugin components
 - `links.yml` - Checks for broken links (uses lychee)
 - `claude-pr-review.yml` - AI-powered PR review
+- `claude.yml` - Claude Code automation
+- `ci-failure-analysis.yml` - Analyzes CI failures
+- `validate-workflows.yml` - Validates GitHub Actions syntax
+- `version-check.yml` - Validates version consistency

plugins/plugin-dev/skills/agent-development/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: agent-development
-description: This skill should be used when the user asks to "create an agent", "add an agent", "write a subagent", "design an agent for [task]", "how do I write agent descriptions", "what are the agent frontmatter fields", "validate my agent", "test agent triggering", "how to restrict agent tools", "what colors can agents use", "autonomous agent", "difference between agent and skill", "agent vs command", "when should I use an agent", "agent schema", or needs guidance on agent structure, system prompts, triggering conditions, or agent development best practices for Claude Code plugins.
+description: This skill provides comprehensive agent development guidance for Claude Code plugins. Use when the user asks to "create an agent", "add an agent", "write a subagent", "agent frontmatter", "validate my agent", "test agent triggering", "agent tools", "agent colors", "autonomous agent", "agent vs skill", "agent vs command", "when to use agents", or needs guidance on agent structure, system prompts, or triggering conditions.
 ---
 
 # Agent Development for Claude Code Plugins