claude-code-mechanism-selector

name	claude-code-mechanism-selector
description	Helps choose the right Claude Code extension mechanism (slash commands, skills, subagents, or hooks) for a given use case. Use when discussing how to extend Claude Code, automate workflows, or implement custom functionality.

Claude Code Mechanism Selector

This skill helps you choose the right extension mechanism for Claude Code based on your requirements.

Quick Decision Guide

Ask these questions to determine the best mechanism:

1. Does it need to run deterministically (guaranteed, not AI-decided)?

• YES → Use Hooks (shell commands at lifecycle events)
• NO → Continue to question 2

2. Does it need a separate context window or specialized AI behavior?

• YES → Use Subagents (isolated context, custom system prompts)
• NO → Continue to question 3

3. Should it activate automatically based on context?

• YES → Use Skills (model-invoked, automatic discovery)
• NO → Use Slash Commands (user-invoked with /command)

Comparison Matrix

Criteria	Slash Commands	Skills	Subagents	Hooks
Invocation	User (/cmd)	Automatic	Automatic or explicit	System events
Complexity	Single file	Multi-file	Separate context	Shell commands
Control	Explicit	Context-based	Task-based	Deterministic
Files	.md only	SKILL.md + resources	.md with frontmatter	JSON config
Scope	Project or user	Project or user	Project or user	Project or user

When to Use Each

Slash Commands

Best for quick, repeatable prompts you want explicit control over.

Examples:

• /review - Review code for bugs
• /explain - Explain code in simple terms
• /commit - Generate commit message

See commands.md for details.

Skills

Best for complex capabilities that should activate automatically.

Examples:

• PDF processing with scripts and templates
• Data analysis with reference documentation
• Code review with checklists and style guides

See skills.md for details.

Subagents

Best for specialized tasks requiring isolated context or custom AI behavior.

Examples:

• Code reviewer with specific review checklist
• Debugger with systematic debugging process
• Data scientist for SQL/BigQuery analysis

See subagents.md for details.

Hooks

Best for deterministic actions that must always happen.

Examples:

• Auto-format code after edits (PostToolUse)
• Log all bash commands (PreToolUse)
• Block edits to sensitive files (PreToolUse)
• Custom notifications (Notification)

See hooks.md for details.

Decision Examples

Use Case	Best Mechanism	Why
"Format code after every edit"	Hooks	Deterministic, must always run
"Quick prompt for code review"	Slash Command	Simple, explicit invocation
"Comprehensive code review system"	Skill or Subagent	Complex, needs structure
"Isolate research from main context"	Subagent	Needs separate context window
"Auto-detect when to apply style guide"	Skill	Should activate automatically
"Log all commands for compliance"	Hooks	Must run every time, deterministic
"Block production file edits"	Hooks	Security rule, must be enforced

Combining Mechanisms

These mechanisms complement each other:

• Skill + Subagent: Skill provides knowledge, subagent provides isolated execution
• Slash Command + Hook: Command triggers workflow, hook ensures formatting
• Subagent + Hook: Subagent does work, hook validates output