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name: claude-expert description: Expert in Claude prompting, skill creation, hooks management, MCP configuration, and sub-agents. Use when writing prompts, creating Claude Code skills, configuring hooks, setting up MCP servers, creating custom sub-agents, or asking about Claude Code architecture. user-invocable: true

Claude Expert Skill

Expert guidance for Claude prompting techniques, Claude Code extensibility, and agent architecture.

Quick Reference

Core Principles

Prompting

• Use XML tags for structure (<context>, <instructions>, <constraints>)
• Be explicit rather than implicit
• Specify format to get formatted output
• Provide examples for complex tasks

Skills

• Skills = markdown files that extend Claude's capabilities
• Description is critical for auto-discovery
• Keep SKILL.md < 500 lines, split into reference files
• Use semantic XML tags in content

Hooks

• PreToolUse hooks validate before execution
• Can block, allow, or ask for confirmation
• Exit codes: 0=allow, 2=block, JSON output for ask

MCP

• Servers defined in ~/.claude/.mcp.json
• Provide external tools and resources
• Use stdio, SSE, or HTTP transport

Sub-agents

• Defined in .claude/agents/ or ~/.claude/agents/
• YAML frontmatter + markdown instructions
• Can specify model, tools, allowed-tools

Workflows

• Variables at top for constants
• Instructions for rules/constraints
• Step-by-step workflow section
• Report template at end

Commands

• Quick-access prompts in .claude/commands/
• Can restrict tools and specify model
• Support argument passing

When to Read Reference Files

Read PROMPTING.md when:

• User asks to write a prompt or system message
• Optimizing an existing prompt
• Structuring complex instructions

Read SKILLS.md when:

• Creating a new skill
• Editing skill YAML frontmatter
• Debugging skill discovery
• Understanding cookbook/prompts patterns

Read WORKFLOWS.md when:

• Building multi-step workflow prompts
• Defining variables and instructions
• Creating orchestrated workflows
• Handling parallel execution

Read COMMANDS.md when:

• Creating /command shortcuts
• Setting up prime or install commands
• Understanding command vs skill differences

Read HOOKS.md when:

• Setting up security validation
• Adding notifications or logging
• Configuring PreToolUse patterns

Read MCP.md when:

• Adding external tool servers
• Configuring MCP resources
• Troubleshooting MCP connections

Read SUBAGENTS.md when:

• Creating custom agents
• Configuring agent tools/permissions
• Understanding Task tool options
• Setting up parallel agent execution
• Managing multi-agent safety