This skill should be used when the user wants to "create a skill", "add a skill to plugin", "write a new skill", "improve skill description", "organize skill content", or needs guidance on skill struc
1---2name: Skill Development3description: This skill should be used when the user wants to "create a skill", "add a skill to plugin", "write a new…4---56# .agents/skills/skill-development/SKILL.md
S
SKILL.mdAgent skill
Transport
File
Status
Listed
SKILL.md
Install
The skill file stays in the publisher's repository.
Paste the copied command in a terminal. It installs this SKILL.md into that agent.
shterminal
1npx skills add scenario-labs/skills --skill skill-development -a cursor -y
Paste the copied command in a terminal. It installs this SKILL.md into that agent.
This skill should be used when the user wants to "create a skill", "add a skill to plugin", "write a new skill", "improve skill description", "organize skill content", or needs guidance on skill structure, progressive disclosure, or skill development best practices for Claude Code plugins.
Download .agents/skills/skill-development/SKILL.md from the publisher, or copy the path and open the repository. PlugMCP lists the skill and does not host the file.
Where does Skill Development live?
The publisher keeps it at https://github.com/scenario-labs/skills.
Which agents can use Skill Development?
Claude, Cursor, Codex, and Grok Build can read a SKILL.md you add from the publisher's repository. Grok Bot installs it when you send the skill's GitHub folder link in a chat.
From the publisher
SKILL.md
name
Skill Development
description
This skill should be used when the user wants to "create a skill", "add a skill to plugin", "write a new skill", "improve skill description", "organize skill content", or needs guidance on skill structure, progressive disclosure, or skill development best practices for Claude Code plugins.
version
0.1.0
Skill Development for Claude Code Plugins
This skill provides guidance for creating effective skills for Claude Code plugins.
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
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)
│ └── 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)
Metadata Quality: The name and description in YAML frontmatter determine when Claude will use the skill. Be specific about what the skill does and when to use it. Use the third-person (e.g. "This skill should be used when..." instead of "Use this skill when...").
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
Example: scripts/rotate_pdf.py for PDF rotation tasks
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
Examples: references/finance.md for financial schemas, references/mnda.md for company NDA template, references/policies.md for company policies, references/api_docs.md for API specifications
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. Prefer references files for detailed information unless it's truly core to the skill—this keeps SKILL.md lean while making information discoverable without hogging the context window. Keep only essential procedural instructions and workflow guidance in SKILL.md; move detailed reference material, schemas, and examples to references files.
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
Examples: assets/logo.png for brand assets, assets/slides.pptx for PowerPoint templates, assets/frontend-template/ for HTML/React boilerplate, assets/font.ttf for typography
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*)
*Unlimited because scripts can be executed without reading into context window.
Skill Creation Process
To create a skill, follow the "Skill Creation Process" in order, skipping steps only if there is a clear reason why they are not applicable.
Step 1: Understanding the Skill with Concrete Examples
Skip this step only when the skill's usage patterns are already clearly understood. It remains valuable even when working with an existing skill.
To create an effective skill, clearly understand concrete examples of how the skill will be used. This understanding can come from either direct user examples or generated examples that are validated with user feedback.
For example, when building an image-editor skill, relevant questions include:
"What functionality should the image-editor skill support? Editing, rotating, anything else?"
"Can you give some examples of how this skill would be used?"
"I can imagine users asking for things like 'Remove the red-eye from this image' or 'Rotate this image'. Are there other ways you imagine this skill being used?"
"What would a user say that should trigger this skill?"
To avoid overwhelming users, avoid asking too many questions in a single message. Start with the most important questions and follow up as needed for better effectiveness.
Conclude this step when there is a clear sense of the functionality the skill should support.
Step 2: Planning the Reusable Skill Contents
To turn concrete examples into an effective skill, analyze each example by:
Considering how to execute on the example from scratch
Identifying what scripts, references, and assets would be helpful when executing these workflows repeatedly
Example: When building a pdf-editor skill to handle queries like "Help me rotate this PDF," the analysis shows:
Rotating a PDF requires re-writing the same code each time
A scripts/rotate_pdf.py script would be helpful to store in the skill
Example: When designing a frontend-webapp-builder skill for queries like "Build me a todo app" or "Build me a dashboard to track my steps," the analysis shows:
Writing a frontend webapp requires the same boilerplate HTML/React each time
An assets/hello-world/ template containing the boilerplate HTML/React project files would be helpful to store in the skill
Example: When building a big-query skill to handle queries like "How many users have logged in today?" the analysis shows:
Querying BigQuery requires re-discovering the table schemas and relationships each time
A references/schema.md file documenting the table schemas would be helpful to store in the skill
For Claude Code plugins: When building a hooks skill, the analysis shows:
Developers repeatedly need to validate hooks.json and test hook scripts
scripts/validate-hook-schema.sh and scripts/test-hook.sh utilities would be helpful
references/patterns.md for detailed hook patterns to avoid bloating SKILL.md
To establish the skill's contents, analyze each concrete example to create a list of the reusable resources to include: scripts, references, and assets.
Step 3: Create Skill Structure
For Claude Code plugins, create the skill directory structure:
Note: Unlike the generic skill-creator which uses init_skill.py, plugin skills are created directly in the plugin's skills/ directory with a simpler manual structure.
Step 4: Edit the Skill
When editing the (newly-created or existing) skill, remember that the skill is being created for another instance of Claude to use. Focus on including information that would be beneficial and non-obvious to Claude. Consider what procedural knowledge, domain-specific details, or reusable assets would help another Claude instance execute these tasks more effectively.
Start with Reusable Skill Contents
To begin implementation, start with the reusable resources identified above: scripts/, references/, and assets/ files. Note that this step may require user input. For example, when implementing a brand-guidelines skill, the user may need to provide brand assets or templates to store in assets/, or documentation to store in references/.
Also, delete any example files and directories not needed for the skill. Create only the directories you actually need (references/, examples/, scripts/).
Update SKILL.md
Writing Style: Write the entire skill using imperative/infinitive form (verb-first instructions), not second person. Use objective, instructional language (e.g., "To accomplish X, do Y" rather than "You should do X" or "If you need to do X"). This maintains consistency and clarity for AI consumption.
Description (Frontmatter): Use third-person format with specific trigger phrases:
---
name: Skill Name
description: This skill should be used when the user asks to "specific phrase 1", "specific phrase 2", "specific phrase 3". Include exact phrases users would say that should trigger this skill. Be concrete and specific.
version: 0.1.0
---
Good description examples:
description: This skill should be used when the user asks to "create a hook", "add a PreToolUse hook", "validate tool use", "implement prompt-based hooks", or mentions hook events (PreToolUse, PostToolUse, Stop).
Bad description examples:
description: Use this skill when working with hooks. # Wrong person, vague
description: Load when user needs hook help. # Not third person
description: Provides hook guidance. # No trigger phrases
To complete SKILL.md body, answer the following questions:
What is the purpose of the skill, in a few sentences?
When should the skill be used? (Include this in frontmatter description with specific triggers)
In practice, how should Claude use the skill? All reusable skill contents developed above should be referenced so that Claude knows how to use them.
Keep SKILL.md lean: Target 1,500-2,000 words for the body. Move detailed content to references/:
Detailed patterns → references/patterns.md
Advanced techniques → references/advanced.md
Migration guides → references/migration.md
API references → references/api-reference.md
Reference resources in SKILL.md:
## Additional Resources
### Reference Files
For detailed patterns and techniques, consult:
- **`references/patterns.md`** - Common patterns
- **`references/advanced.md`** - Advanced use cases
### Example Files
Working examples in `examples/`:
- **`example-script.sh`** - Working example
Step 5: Validate and Test
For plugin skills, validation is different from generic skills:
Check structure: Skill directory in plugin-name/skills/skill-name/
Validate SKILL.md: Has frontmatter with name and description
Check trigger phrases: Description includes specific user queries
Verify writing style: Body uses imperative/infinitive form, not second person
Test progressive disclosure: SKILL.md is lean (~1,500-2,000 words), detailed content in references/
Check references: All referenced files exist
Validate examples: Examples are complete and correct
Test scripts: Scripts are executable and work correctly
Use the skill-reviewer agent:
Ask: "Review my skill and check if it follows best practices"
The skill-reviewer agent will check description quality, content organization, and progressive disclosure.
Step 6: Iterate
After testing the skill, users may request improvements. Often this happens right after using the skill, with fresh context of how the skill performed.
Iteration workflow:
Use the skill on real tasks
Notice struggles or inefficiencies
Identify how SKILL.md or bundled resources should be updated
Implement changes and test again
Common improvements:
Strengthen trigger phrases in description
Move long sections from SKILL.md to references/
Add missing examples or scripts
Clarify ambiguous instructions
Add edge case handling
Plugin-Specific Considerations
Skill Location in Plugins
Plugin skills live in the plugin's skills/ directory:
Body is focused and lean (1,500-2,000 words ideal, <5k max)
Detailed content moved to references/
Examples are complete and working
Scripts are executable and documented
Progressive Disclosure:
Core concepts in SKILL.md
Detailed docs in references/
Working code in examples/
Utilities in scripts/
SKILL.md references these resources
Testing:
Skill triggers on expected user queries
Content is helpful for intended tasks
No duplicated information across files
References load when needed
Common Mistakes to Avoid
Mistake 1: Weak Trigger Description
❌ Bad:
description: Provides guidance for working with hooks.
Why bad: Vague, no specific trigger phrases, not third person
✅ Good:
description: This skill should be used when the user asks to "create a hook", "add a PreToolUse hook", "validate tool use", or mentions hook events. Provides comprehensive hooks API guidance.
Why good: Third person, specific phrases, concrete scenarios
Mistake 2: Too Much in SKILL.md
❌ Bad:
skill-name/
└── SKILL.md (8,000 words - everything in one file)
Focus on strong trigger descriptions, progressive disclosure, and imperative writing style for effective skills that load when needed and provide targeted guidance.