Skill Creator

Skill Creator

Guidance for creating effective AgentSkills for AgentKthx.

What Are Skills?

Skills are modular packages that extend an agent's capabilities by providing specialized knowledge, workflows, and tools. Think of them as "onboarding guides" for specific domains or tasks.

Skill Structure

skill-name/
├── SKILL.md (required)
│   ├── YAML frontmatter (required)
│   │   ├── name: skill-name
│   │   └── description: When and how to use this skill
│   └── Markdown instructions
└── Bundled Resources (optional)
    ├── scripts/    - Executable code (Python/Bash)
    ├── references/ - Documentation loaded as needed
    └── assets/     - Templates, images, files for output

Core Principles

Be Concise

The context window is limited. Only add information the model doesn't already know. Prefer concise examples over verbose explanations.

Match Freedom to Task

• High freedom (text instructions): Multiple approaches valid
• Medium freedom (pseudocode): Preferred pattern exists
• Low freedom (specific scripts): Exact sequence required

Progressive Disclosure

Skills use a three-level loading system:

1. Metadata (~100 tokens): name + description - always visible
2. Instructions (<500 lines): SKILL.md body - loaded when skill triggers
3. Resources (as needed): scripts, references, assets - loaded on demand

Keep SKILL.md under 500 lines. Split content into references/ when approaching this limit.

Creating a Skill

Step 1: Define the Skill

Understand concrete usage examples:

• What functionality should it support?
• What would trigger this skill?
• What reusable resources would help?

Step 2: Initialize

Use the init script to create the skill structure:

python scripts/init_skill.py <skill-name> --path <output-dir> [--resources scripts,references,assets]

Step 3: Write SKILL.md

Frontmatter:

---
name: my-skill
description: What the skill does and when to use it. Include trigger phrases.
---

Body: Write instructions for using the skill and its resources.

Step 4: Add Resources (Optional)

• scripts/: Tested, working code for repetitive tasks
• references/: Documentation, schemas, examples
• assets/: Templates, images, boilerplate

Step 5: Validate & Package

python scripts/validate.py <skill-folder>  # Check structure
python scripts/package_skill.py <skill-folder>  # Create .skill file

Skill Naming

• Lowercase letters, digits, hyphens only
• Under 64 characters
• Verb-led phrases preferred (e.g., pdf-rotate, code-review)
• Folder name matches skill name

Avoid

Do NOT create these files - they add clutter:

• README.md
• INSTALLATION_GUIDE.md
• CHANGELOG.md
• QUICK_REFERENCE.md

A skill should only contain what an AI agent needs to do the job.