| name | skill-creator |
| description | Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends Claude's capabilities with specialized knowledge, workflows, or tool integrations. |
| license | Complete terms in LICENSE.txt |
Skill Creator
This skill provides guidance for creating effective skills.
About Skills
Skills are modular, self-contained packages that extend Claude's capabilities by providing
specialized knowledge, workflows, and tools. Think of them as "onboarding guides" for specific
domains or tasks—they transform Claude from a general-purpose agent into a specialized agent
equipped with procedural knowledge that no model can fully possess.
What Skills Provide
- Specialized workflows - Multi-step procedures for specific domains
- Tool integrations - Instructions for working with specific file formats or APIs
- Domain expertise - Company-specific knowledge, schemas, business logic
- Bundled resources - Scripts, references, and assets for complex and repetitive tasks
Core Principles
Concise is Key
The context window is a public good. Skills share the context window with everything else Claude needs: system prompt, conversation history, other Skills' metadata, and the actual user request.
Default assumption: Claude is already very smart. Only add context Claude doesn't already have. Challenge each piece of information: "Does Claude really need this explanation?" and "Does this paragraph justify its token cost?"
Prefer concise examples over verbose explanations.
Set Appropriate Degrees of Freedom
Match the level of specificity to the task's fragility and variability:
High freedom (text-based instructions): Use when multiple approaches are valid, decisions depend on context, or heuristics guide the approach.
Medium freedom (pseudocode or scripts with parameters): Use when a preferred pattern exists, some variation is acceptable, or configuration affects behavior.
Low freedom (specific scripts, few parameters): Use when operations are fragile and error-prone, consistency is critical, or a specific sequence must be followed.
Think of Claude as exploring a path: a narrow bridge with cliffs needs specific guardrails (low freedom), while an open field allows many routes (high freedom).
Anatomy of a Skill
Every skill consists of a required SKILL.md file and optional bundled resources:
skill-name/
├── SKILL.md (required)
│ ├── YAML frontmatter metadata (required)
│ │ ├── name: (required)
│ │ ├── description: (required)
│ │ └── compatibility: (optional, rarely needed)
│ └── Markdown instructions (required)
└── Bundled Resources (optional)
├── scripts/ - Executable code (Python/Bash/etc.)
├── references/ - Documentation intended to be loaded into context as needed
└── assets/ - Files used in output (templates, icons, fonts, etc.)
SKILL.md (required)
Every SKILL.md consists of:
- Frontmatter (YAML): Contains
name and description fields (required), plus optional fields like license, metadata, and compatibility. Only name and description are read by Claude to determine when the skill triggers, so be clear and comprehensive about what the skill is and when it should be used. The compatibility field is for noting environment requirements (target product, system packages, etc.) but most skills don't need it.
- Body (Markdown): Instructions and guidance for using the skill. Only loaded AFTER the skill triggers (if at all).
Bundled Resources (optional)
Scripts (scripts/)
Executable code (Python/Bash/etc.) for tasks that require deterministic reliability or are repeatedly rewritten.
- When to include: When the same code is being rewritten repeatedly or deterministic reliability is needed
- Benefits: Token efficient, deterministic, may be executed without loading into context
- Note: Scripts may still need to be read by Claude for patching or environment-specific adjustments
References (references/)
Documentation and reference material intended to be loaded as needed into context to inform Claude's process and thinking.
- When to include: For documentation that Claude should reference while working
- Use cases: Database schemas, API documentation, domain knowledge, company policies, detailed workflow guides
- Benefits: Keeps SKILL.md lean, loaded only when Claude determines it's needed
- Best practice: If files are large (>10k words), include grep search patterns in SKILL.md
- Avoid duplication: Information should live in either SKILL.md or references files, not both.
Assets (assets/)
Files not intended to be loaded into context, but rather used within the output Claude produces.
- When to include: When the skill needs files that will be used in the final output
- Use cases: Templates, images, icons, boilerplate code, fonts, sample documents that get copied or modified
- Benefits: Separates output resources from documentation, enables Claude to use files without loading them into context
Progressive Disclosure Design Principle
Skills use a three-level loading system to manage context efficiently:
- Metadata (name + description) - Always in context (~100 words)
- SKILL.md body - When skill triggers (<5k words)
- Bundled resources - As needed by Claude (Unlimited because scripts can be executed without reading into context window)
Keep SKILL.md body to the essentials and under 500 lines. Split content into separate files when approaching this limit. When splitting out content, reference them from SKILL.md and describe clearly when to read them.
Skill Creation Process
- Understand the skill with concrete examples
- Plan reusable skill contents (scripts, references, assets)
- Initialize the skill (run init_skill.py)
- Edit the skill (implement resources and write SKILL.md)
- Package the skill (run package_skill.py)
- Iterate based on real usage
Step 1: Understanding the Skill with Concrete Examples
Clearly understand concrete examples of how the skill will be used. Ask questions like:
- "What functionality should this skill support?"
- "Can you give examples of how it would be used?"
- "What would a user say that should trigger this skill?"
Step 2: Planning the Reusable Skill Contents
Analyze each example by considering how to execute it from scratch, then identify what scripts, references, and assets would be helpful for repeated execution.
Step 3: Initializing the Skill
Run the init script to create the template:
scripts/init_skill.py <skill-name> --path <output-directory>
Step 4: Edit the Skill
Remember: the skill is being created for another instance of Claude to use. Include information that would be beneficial and non-obvious.
Consult these guides based on your skill's needs:
- Multi-step processes: See references/workflows.md
- Specific output formats or quality standards: See references/output-patterns.md
Frontmatter
name: The skill name
description: Primary triggering mechanism. Include both what the skill does AND when to use it. All "when to use" information goes here, not in the body.
Body
Write instructions for using the skill and its bundled resources.
Step 5: Packaging a Skill
scripts/package_skill.py <path/to/skill-folder> [output-directory]
The script validates and then creates a .skill file (zip format) for distribution.
Step 6: Iterate
- Use the skill on real tasks
- Notice struggles or inefficiencies
- Update SKILL.md or bundled resources
- Test again