Agent Skills: Skill Creator

Skill Creator

Overview

This skill guides the creation of new Codex skills. Skills are specialized instruction sets that enhance Codex's capabilities for specific domains, tasks, or workflows.

When to Use

• Building custom skills for specific domains
• Creating reusable workflow templates
• Standardizing organizational processes
• Extending Codex capabilities
• Documenting specialized knowledge

Quick Start

1. Define scope - Answer: What problem? Who uses it? What outputs?
2. Create structure - .Codex/skills/skill-name/SKILL.md
3. Write frontmatter - Name, description, version, category
4. Add content - Overview, Instructions, Examples, Best Practices
5. Test - Verify skill triggers correctly

# Create skill directory
mkdir -p .Codex/skills/my-new-skill

# Create SKILL.md with template
cat > .Codex/skills/my-new-skill/SKILL.md << 'EOF'
---
name: my-new-skill
description: Action-oriented description. Use for X, Y, and Z.
version: 1.0.0
category: [builders|tools|content-design|communication|meta]
tags: [topic-keyword, tool-name, use-case]  # discovery tags for search/filtering
related_skills: [companion-skill-name]     # cross-references to sibling skills
freedom: medium  # high = open-ended (brainstorming, research); medium = structured output (reports, templates); low = strict procedure (deploy, migrate, verify)
---

# My New Skill

## Overview
[1-2 sentences explaining purpose]

## When to Use
- Scenario 1
- Scenario 2

## Prerequisites
- Dependency 1
- Dependency 2

## Version History
- **1.0.0** (YYYY-MM-DD): Initial release
EOF

Prerequisites

• Familiarity with YAML frontmatter
• Understanding of markdown structure
• Knowledge of the skill category taxonomy

Deprecation

When retiring a skill:

---
name: old-skill-name
description: DEPRECATED - Use new-skill-name instead. [Original description]
deprecated: true
deprecated_date: 2026-01-02
replacement: new-skill-name
---

Quality Tiers

Skills are classified into quality tiers (A/B/C/D) based on enforcement level:

• Tier A — Script-wired: frontmatter scripts: list with >=1 entry
• Tier B — Exec-pattern: body contains bash scripts/, uv run, or bash .Codex/skills/
• Tier D — Decomposition candidate: >500 words with no script refs (split recommended)
• Tier C — Focused prose: everything else

Target Tier A or B for new skills. See config/skills/quality-tiers.yaml.

Related Skills

• coordination/session-start-routine/SKILL.md - Skill library maintenance
• sparc-workflow - Development methodology
• mcp-builder - MCP server creation

Version History

• 2.2.0 (2026-03-05): Deduplicated hub SKILL.md; trimmed to <200 lines
• 2.1.0 (2026-03-04): Synced critical rules with Anthropic official guide
• 2.0.0 (2026-01-02): Upgraded to v2 template
• 1.0.0 (2024-10-15): Initial release

Sub-Skills

• Official Plugin Reference
• Canonical Reference
• Instructions
• File Structure (+1)
• Error Handling
• Metrics
• 1. Clear Triggering (+1)
• Detailed Instructions
• 3. Multi-Stage Workflow Architecture (+1)
• Bad: Conceptual only
• Good: Actionable
• Step 1: Define the Skill Scope (+2)
• [Task Category 1] (+1)
• Technical Skill Template
• Installation
• Operation 1 (+1)
• Configuration Options
• Common Errors
• Step 1: [Name] (+2)
• [Template Name]
• Creative Skill Template
• Principle 1: [Name] (+1)
• Style 1: [Name] (+1)
• Phase 1: [Name] (+1)
• Technical Implementation
• Quality Checklist
• Inspiration & Examples
• Examples
• Best Practices
• Advanced Usage
• Execution Checklist
• Content Quality (+3)
• Versioning
• Skill Discovery (+2)
• Process Skill Template
• [Scenario]