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.
Guides users through creating effective Claude skills with specialized workflows, tools, and domain knowledge.
/plugin marketplace add jamie-bitflight/claude_skills/plugin install plugin-creator@jamie-bitflight-skillsskill-creator/This skill provides guidance for creating effective 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.
This skill is for creating NEW skills from scratch. For refactoring EXISTING skills (splitting oversized skills, reorganizing multi-domain skills), use the skill-refactor skill:
Skill(command: "refactor-skill")
When to use skill-creator vs skill-refactor:
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.
Skills use progressive disclosure to manage context efficiently:
<available_skills> block (~100 words per skill)Budget Constraints:
| Resource | Limit | Notes |
|---|---|---|
name field | 64 chars | Lowercase, numbers, hyphens only |
description field | 1024 chars | Critical for skill selection |
<available_skills> block | ~15,000 chars | Separate from global context window, includes ALL skill metadata |
| Skills before truncation | ~34-36 | Varies by description complexity and length |
Truncation Behavior:
When total skill metadata exceeds ~15,000 characters:
<available_skills> block/skill-name/context to check for a warning about excluded skillsTo increase the limit, set the SLASH_COMMAND_TOOL_CHAR_BUDGET environment variable.
Fallback Strategy:
If you have many skills, embed pointers in CLAUDE.md as a safeguard:
## Skills Available
- For debugging: use `/scientific-thinking` skill
- For delegation: use `/delegate` skill
This ensures Claude can find skills even if truncated from <available_skills>.
CRITICAL YAML BUG:
Do NOT use YAML multiline indicators in descriptions:
# WRONG - will show ">-" as description
description: >-
This is a multiline description that breaks.
# WRONG - same problem
description: |-
This breaks too.
# CORRECT - single quoted string
description: 'This works correctly. Use single quotes for descriptions with special characters or keep on one line.'
The Claude Code skill indexer does not parse YAML multiline indicators correctly - the description appears as ">-" instead of actual content.
SOURCE: claude-skills-overview-2026 section on Skill Tokenomics.
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).
Every skill consists of a required SKILL.md file and optional bundled resources:
skill-name/
├── SKILL.md (required)
│ ├── YAML frontmatter metadata (required)
│ │ └── description: (recommended)
│ │ └── ⚠️ DO NOT include 'name:' field (Claude Code bug - prevents slash command registration)
│ └── 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.)
Every SKILL.md consists of:
name, description, argument-hint, allowed-tools, model, context, user-invocable, disable-model-invocation, and hooks. The description field (or first paragraph if omitted) is what Claude reads to determine when the skill gets used, thus it is very important to be clear and comprehensive in describing what the skill is and when it should be used.scripts/)Executable code (Python/Bash/etc.) for tasks that require deterministic reliability or are repeatedly rewritten.
scripts/rotate_pdf.py for PDF rotation tasksreferences/)Documentation and reference material intended to be loaded as needed into context to inform Claude's process and thinking.
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 specificationsassets/)Files not intended to be loaded into context, but rather used within the output Claude produces.
assets/logo.png for brand assets, assets/slides.pptx for PowerPoint templates, assets/frontend-template/ for HTML/React boilerplate, assets/font.ttf for typographyA skill should only contain essential files that directly support its functionality. Do NOT create extraneous documentation or auxiliary files, including:
The skill should only contain the information needed for an AI agent to do the job at hand. It should not contain auxilary context about the process that went into creating it, setup and testing procedures, user-facing documentation, etc. Creating additional documentation files just adds clutter and confusion.
Add context: fork to frontmatter when you want a skill to run in isolation without access to conversation history.
When to use:
When NOT to use:
Agent types:
context: fork
agent: Explore # or Plan, general-purpose, custom-agent-name
| Agent | Model | Tools | Use Case |
|---|---|---|---|
Explore | Haiku | File/web/MCP (read-only) | Fast codebase analysis |
Plan | Inherits | File/web/MCP (read-only) | Research before planning |
general-purpose | Inherits | File/web/MCP + Bash/system | Complex operations (default) |
Tool restrictions:
context: fork)SOURCE: claude-skills-overview-2026 section on Context Fork Behavior.
Control who can invoke your skill:
Default behavior: Both user and Claude can invoke
/skill-nameManual-only (disable auto-invoke):
disable-model-invocation: true
/skill-name/deploy, /send-slack-message)Background knowledge (hide from menu):
user-invocable: false
/ autocomplete menu/legacy-system-context)/legacy-system-context isn't a meaningful user actionSOURCE: claude-skills-overview-2026 section on Invocation Control.
Skills can define hooks in frontmatter to respond to events during the skill's lifecycle:
Events:
PreToolUse - Before tool executesPostToolUse - After successful executionStop - When skill finishesExample:
hooks:
PreToolUse:
- matcher: "Bash" # Regex pattern matching tool name
hooks:
- type: command
command: "./scripts/check.sh"
once: true # Run only once per session
PostToolUse:
- matcher: "Write|Edit"
hooks:
- type: command
command: "./scripts/lint.sh"
Stop:
- hooks:
- type: command
command: "./scripts/cleanup.sh"
Hook I/O:
Complete documentation: See claude-hooks-reference-2026 for all events, matchers, JSON output control, and examples.
SOURCE: claude-skills-overview-2026 section on Hooks in Skills.
Skills use a three-level loading system to manage context efficiently:
Keep SKILL.md body to the essentials and under 500 lines to minimize context bloat. Split content into separate files when approaching this limit. When splitting out content into other files, it is very important to reference them from SKILL.md and describe clearly when to read them, to ensure the reader of the skill knows they exist and when to use them.
Key principle: When a skill supports multiple variations, frameworks, or options, keep only the core workflow and selection guidance in SKILL.md. Move variant-specific details (patterns, examples, configuration) into separate reference files.
Pattern 1: High-level guide with references
# PDF Processing
## Quick start
Extract text with pdfplumber:
[code example]
## Advanced features
- **Form filling**: See [FORMS.md](FORMS.md) for complete guide
- **API reference**: See [REFERENCE.md](REFERENCE.md) for all methods
- **Examples**: See [EXAMPLES.md](EXAMPLES.md) for common patterns
Claude loads FORMS.md, REFERENCE.md, or EXAMPLES.md only when needed.
Pattern 2: Domain-specific organization
For Skills with multiple domains, organize content by domain to avoid loading irrelevant context:
bigquery-skill/
├── SKILL.md (overview and navigation)
└── reference/
├── finance.md (revenue, billing metrics)
├── sales.md (opportunities, pipeline)
├── product.md (API usage, features)
└── marketing.md (campaigns, attribution)
When a user asks about sales metrics, Claude only reads sales.md.
Similarly, for skills supporting multiple frameworks or variants, organize by variant:
cloud-deploy/
├── SKILL.md (workflow + provider selection)
└── references/
├── aws.md (AWS deployment patterns)
├── gcp.md (GCP deployment patterns)
└── azure.md (Azure deployment patterns)
When the user chooses AWS, Claude only reads aws.md.
Pattern 3: Conditional details
Show basic content, link to advanced content:
# DOCX Processing
## Creating documents
Use docx-js for new documents. See [DOCX-JS.md](DOCX-JS.md).
## Editing documents
For simple edits, modify the XML directly.
**For tracked changes**: See [REDLINING.md](REDLINING.md)
**For OOXML details**: See [OOXML.md](OOXML.md)
Claude reads REDLINING.md or OOXML.md only when the user needs those features.
Important guidelines:
Skill creation involves these steps:
Follow these steps in order, skipping only if there is a clear reason why they are not applicable.
Before creating a skill, decide where it will live. If unclear, STOP and ask the user.
| Location | Purpose | Distribution | Use When |
|---|---|---|---|
| Plugin (bundled) | plugins/*/skills/ | Via plugin marketplace | Creating reusable skills for public/team distribution |
| Project (version control) | .claude/skills/ | Via git (team-shared) | Project-specific skills shared with team via version control |
| User (personal) | ~/.claude/skills/ | Manual (personal use) | Personal skills used across all your projects |
Location priority when skills share same name: managed/enterprise > user (~/.claude/skills/) > project (.claude/skills/). Plugin skills use plugin-name:skill-name namespace and don't conflict with other levels.
CRITICAL: Packaging (step 6) is ONLY needed for plugin distribution. If creating skills in .claude/skills/ or ~/.claude/skills/, they are already in their final location - skip the packaging step entirely.
Automatic discovery: Claude Code automatically discovers skills from nested .claude/skills/ directories. For example, if editing packages/frontend/, Claude also looks in packages/frontend/.claude/skills/. This supports monorepo setups where packages have their own skills.
When location is unclear: STOP and ask: "Where should this skill be created? (1) Plugin for marketplace distribution, (2) Project-level (.claude/skills/) for team sharing via git, or (3) User-level (~/.claude/skills/) for personal use?"
SOURCE: claude-skills-overview-2026 section on Directory Structure and Location Priority.
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:
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.
To turn concrete examples into an effective skill, analyze each example by:
Example: When building a pdf-editor skill to handle queries like "Help me rotate this PDF," the analysis shows:
scripts/rotate_pdf.py script would be helpful to store in the skillExample: 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:
assets/hello-world/ template containing the boilerplate HTML/React project files would be helpful to store in the skillExample: When building a big-query skill to handle queries like "How many users have logged in today?" the analysis shows:
references/schema.md file documenting the table schemas would be helpful to store in the skillTo establish the skill's contents, analyze each concrete example to create a list of the reusable resources to include: scripts, references, and assets.
CRITICAL: This is the MANDATORY first step for creating ANY skill. Do NOT skip this step.
For ALL skills (plugin, project, and user):
Run the init_skill.py script. This script generates a complete template skill directory with:
scripts/, references/, assets/)Usage:
# The script has executable permissions and a shebang - run it directly
${CLAUDE_PLUGIN_ROOT}/scripts/init_skill.py <skill-name> --path <output-directory>
Examples:
# Plugin skill
${CLAUDE_PLUGIN_ROOT}/scripts/init_skill.py my-new-skill --path plugins/my-plugin/skills
# Project skill
${CLAUDE_PLUGIN_ROOT}/scripts/init_skill.py my-skill --path .claude/skills
# User skill
${CLAUDE_PLUGIN_ROOT}/scripts/init_skill.py my-skill --path ~/.claude/skills
What the script does:
scripts/, references/, assets/ directoriesIMPORTANT: Do NOT manually create skill directories. The script provides essential scaffolding, validation, and examples that manual creation misses.
Only skip if: The skill directory already exists and you're iterating on an existing skill.
After initialization, customize or remove the generated SKILL.md and example files as needed.
When editing the (newly-generated or existing) skill, remember that the skill is being created for another instance of Claude to use. Include 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.
Consult these helpful guides based on your skill's needs:
These files contain established best practices for effective skill design.
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/.
Added scripts must be tested by actually running them to ensure there are no bugs and that the output matches what is expected. If there are many similar scripts, only a representative sample needs to be tested to ensure confidence that they all work while balancing time to completion.
Any example files and directories not needed for the skill should be deleted. The initialization script creates example files in scripts/, references/, and assets/ to demonstrate structure, but most skills won't need all of them.
Writing Guidelines: Always use imperative/infinitive form.
Write the YAML frontmatter. All fields are optional, but description is strongly recommended:
name: Optional. The skill name (defaults to directory name if omitted). Lowercase letters, numbers, and hyphens only. Max 64 characters.description: Optional but strongly recommended. This is the primary triggering mechanism for your skill, and helps Claude understand when to use the skill. If omitted, uses the first paragraph of markdown content.
>-, |-, |) - they are broken and will display as ">-" instead of your text. Use single-line quoted strings instead.docx skill: "Comprehensive document creation, editing, and analysis with support for tracked changes, comments, formatting preservation, and text extraction. Use when Claude needs to work with professional documents (.docx files) for: (1) Creating new documents, (2) Modifying or editing content, (3) Working with tracked changes, (4) Adding comments, or any other document tasks"argument-hint: Optional. Hint shown during autocomplete to indicate expected arguments. Example: [issue-number] or [filename] [format].allowed-tools: Optional. Tools Claude can use without asking permission when this skill is active (comma-separated). Example: Read, Grep, Glob, Bash(npm run:*)model: Optional. Model to use when this skill is active. Options: claude-opus-4-5-20251101, claude-sonnet-4-20250514, opus, sonnet, haikucontext: Optional. Set to fork to run in a forked subagent context for isolation. See advanced patterns below.agent: Optional. Which subagent type to use when context: fork is set. Options: Explore, Plan, general-purpose, or custom agent name.user-invocable: Optional. Set to false to hide from the / menu. Use for background knowledge users shouldn't invoke directly. Default: true.disable-model-invocation: Optional. Set to true to prevent Claude from automatically loading this skill. Use for workflows you want to trigger manually with /name. Default: false.hooks: Optional. Hooks scoped to this skill's lifecycle. See hooks documentation for configuration format.Complete field reference: See claude-skills-overview-2026 skill for definitive schema documentation.
Write instructions for using the skill and its bundled resources.
Advanced Body Features:
String Substitutions - Skills support dynamic value replacement:
$ARGUMENTS - All arguments passed when invoking the skill$ARGUMENTS[N] or $N - Specific argument by 0-based index (e.g., $0, $1)${CLAUDE_SESSION_ID} - Current session ID for logging or session-specific filesExample:
---
description: Migrate a component from one framework to another
# NOTE: Do NOT add 'name:' field for plugin skills (Claude Code bug)
# Skill name comes from directory name automatically
---
Migrate the $0 component from $1 to $2.
Preserve all existing behavior and tests.
Running /migrate-component SearchBar React Vue replaces $0 with SearchBar, $1 with React, and $2 with Vue.
Dynamic Context Injection - Preprocess shell commands before skill content reaches Claude:
Example (summarize GitHub PR):
---
description: Summarize GitHub pull request changes
# NOTE: Do NOT add 'name:' field for plugin skills (Claude Code bug)
# Skill name comes from directory name automatically
---
Pull Request Data:
\`\!\`gh pr view $0 --json title,body,commits\`\`\`
Create a summary of the changes above.
Extended Thinking Mode - Include the word "ultrathink" anywhere in skill content to enable extended thinking mode for complex reasoning tasks.
SOURCE: claude-skills-overview-2026 sections on String Substitutions and Dynamic Context Injection.
IMPORTANT: This step is ONLY required when distributing skills via plugins. Skip this step if:
.claude/skills/ (project-level, shared via git)~/.claude/skills/ (user-level, personal use)Only for plugin skills:
Once development of the skill is complete and you plan to distribute it via a plugin, package it into a distributable .skill file. The packaging process automatically validates the skill first to ensure it meets all requirements:
scripts/package_skill.py <path/to/skill-folder>
Optional output directory specification:
scripts/package_skill.py <path/to/skill-folder> ./dist
The packaging script will:
Validate the skill automatically, checking:
Package the skill if validation passes, creating a .skill file named after the skill (e.g., my-skill.skill) that includes all files and maintains the proper directory structure for distribution. The .skill file is a zip file with a .skill extension.
If validation fails, the script will report the errors and exit without creating a package. Fix any validation errors and run the packaging command again.
Alternative: Bundle in Plugin Directly
Instead of creating standalone .skill files, you can include skills directly in a plugin's skills/ directory and reference them in plugin.json. This is the recommended approach for plugin-bundled skills. See claude-plugins-reference-2026 for plugin creation documentation.
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: