skill-master

name	skill-master
description	Agent Skills authoring. Covers SKILL.md format, frontmatter, folders, docs ingestion. Keywords: agentskills.io, SKILL.md.
version	1.2.4
release_date	2026-02-06
metadata	{"author":"itechmeat"}

Skill Master

This skill is the entry point for creating and maintaining Agent Skills.

Language requirement: all skills MUST be authored in English.

Quick Navigation

• New to skills? Read: references/specification.md
• SKILL.md templates? See: assets/skill-templates.md
• Advanced features (context, agents, hooks)? Read: references/advanced-features.md
• Creating from docs? Read: references/docs-ingestion.md
• Validation & packaging? See scripts/

When to Use

• Creating a new skill from scratch
• Updating an existing skill
• Creating a skill by ingesting external documentation
• Validating or packaging a skill for distribution

Skill Structure (Required)

my-skill/
├── SKILL.md          # Required: instructions + metadata
├── README.md         # Optional: human-readable description
├── metadata.json     # Optional: extended metadata for publishing
├── references/       # Optional: documentation, guides, API references
├── examples/         # Optional: sample outputs, usage examples
├── scripts/          # Optional: executable code
└── assets/           # Optional: templates, images, data files

Folder Purposes (CRITICAL)

Folder	Purpose	Examples
references/	Documentation for agents to read	Guides, API docs, concept explanations, troubleshooting
examples/	Sample outputs showing expected format	Output examples, usage demonstrations
assets/	Static resources to copy/use	Document templates, config templates, images, schemas
scripts/	Executable code to run	Python scripts, shell scripts, validators

When to Use Each

Use references/ for:

• Detailed documentation about concepts
• API references and usage guides
• Troubleshooting and FAQ
• Anything the agent needs to read and understand

Use examples/ for:

• Sample outputs showing expected format
• Usage demonstrations
• Before/after comparisons
• Anything showing what the result should look like

Use assets/ for:

• Document templates (markdown files to copy as starting point)
• Configuration file templates
• Schema files, lookup tables
• Images and diagrams
• Anything the agent needs to copy or reference verbatim

IMPORTANT: Templates belong in assets/, examples in examples/, documentation in references/.

Frontmatter Schema

Every SKILL.md MUST start with YAML frontmatter:

---
name: skill-name
description: "What it does. Keywords: term1, term2."
metadata:
  author: your-name
  version: "1.0.0"
---

Field order: name → description → license → compatibility → metadata → other fields

Required Fields

Field	Constraints
name	1-64 chars, lowercase a-z0-9-, no --, no leading/trailing -, must match folder name
description	1-1024 chars (target: 80-150), describes what skill does + when to use it, include keywords

Optional Fields (Top Level)

Field	Purpose
license	License name or reference to bundled LICENSE file
compatibility	Environment requirements (max 500 chars)
metadata	Object for arbitrary key-value pairs (see below)

metadata Object (Common Fields)

Field	Purpose
author	Author name or organization
version	Skill version (semver format, e.g., "1.0.0")
argument-hint	Hint for autocomplete, e.g., [issue-number]

IMPORTANT: version in metadata is the skill version. If you reference external product docs, track that version separately (e.g., in README.md or metadata.json).

Optional Fields (Claude Code / Advanced)

Field	Purpose
disable-model-invocation	true = only user can invoke (via /name). Default: false
user-invocable	false = hidden from / menu, only agent can load. Default: true
allowed-tools	Space-delimited tools agent can use without asking, e.g., Read Grep Glob
model	Specific model to use when skill is active
context	Set to fork to run in a forked subagent context
agent	Subagent type when context: fork, e.g., Explore, Plan
hooks	Hooks scoped to skill's lifecycle (see agent documentation)

Invocation Control Matrix

Frontmatter	User can invoke	Agent can invoke	Notes
(default)	✅ Yes	✅ Yes	Description in context, loads when used
disable-model-invocation: true	✅ Yes	❌ No	For manual workflows with side effects
user-invocable: false	❌ No	✅ Yes	Background knowledge, not a command

Variable Substitutions

Available placeholders in skill content:

Variable	Description
$ARGUMENTS	All arguments passed when invoking the skill
${CLAUDE_SESSION_ID}	Current session ID for logging or session-specific files

If $ARGUMENTS is not in content, arguments are appended as ARGUMENTS: <value>.

Example:

---
name: fix-issue
description: Fix a GitHub issue
disable-model-invocation: true
---
Fix GitHub issue $ARGUMENTS following our coding standards.

Dynamic Context Injection

Use !command`` syntax to run shell commands before skill content is sent to the agent:

## Pull request context

- PR diff: !`gh pr diff`
- Changed files: !`gh pr diff --name-only`

## Your task

Review this pull request...

The command output replaces the placeholder, so the agent receives actual data.

metadata.json (Optional)

For publishing or extended metadata, create metadata.json:

{
  "version": "1.0.0",
  "organization": "Your Org",
  "date": "January 2026",
  "abstract": "Brief description of what this skill provides...",
  "references": ["https://docs.example.com", "https://github.com/org/repo"]
}

Fields:

• version — Skill version (semver)
• organization — Author or organization
• date — Publication date
• abstract — Extended description (can be longer than frontmatter)
• references — List of source documentation URLs

Name Validation Examples

# Valid
name: pdf-processing
name: data-analysis
name: code-review

# Invalid
name: PDF-Processing  # uppercase not allowed
name: -pdf            # cannot start with hyphen
name: pdf--processing # consecutive hyphens not allowed

Description Rules

Purpose: Tell the LLM what the skill does and when to activate it. Minimize tokens — just enough for activation decision.

Formula:

[Product] [core function]. Covers [2-3 key topics]. Keywords: [terms].

Constraints:

• Target: 80-150 chars
• Max: 300 chars
• No marketing ("powerful", "comprehensive", "modern")
• No filler ("this skill", "use this for", "helps with")
• No redundant context (skip "for apps", "for developers")

Good examples:

description: "Turso SQLite database. Covers encryption, sync, agent patterns. Keywords: Turso, libSQL, SQLite."

description: "Base UI unstyled React components. Covers forms, menus, overlays. Keywords: @base-ui/react, render props."

description: "Inworld TTS API. Covers voice cloning, audio markups, timestamps. Keywords: Inworld, TTS, visemes."

Poor examples:

# Too vague
description: "Helps with PDFs."

# Too verbose
description: "Turso embedded SQLite database for modern apps and AI agents. Covers encryption, authorization, sync, partial sync, and agent database patterns."

# Marketing
description: "A powerful solution for all your database needs."

Keywords: product name, package name, 3-5 terms max.

How Skills Work (Progressive Disclosure)

1. Discovery: Agent loads only name + description of each skill (~50-100 tokens)
2. Activation: When task matches, agent reads full SKILL.md into context
3. Execution: Agent follows instructions, loads referenced files as needed

Key rule: Keep SKILL.md under 500 lines. Move details to references/.

Creating a New Skill

Step 1: Scaffold

python scripts/init_skill.py <skill-name>
# Or specify custom directory:
python scripts/init_skill.py <skill-name> --skills-dir skills

Or manually create:

<skills-folder>/<skill-name>/
├── SKILL.md
├── references/   # For documentation, guides
└── assets/       # For templates, static files

Step 2: Write Frontmatter

---
name: <skill-name>
description: "[Purpose] + [Triggers/Keywords]"
---

Step 3: Write Body

Recommended sections:

• When to use (triggers, situations)
• Quick navigation (router to references and assets)
• Steps / Recipes / Checklists
• Critical prohibitions
• Links

Step 4: Add References (documentation)

For each major topic, create references/<topic>.md with:

• Actionable takeaways (5-15 bullets)
• Gotchas / prohibitions
• Practical examples

Step 5: Add Assets (if needed)

For templates or static resources, create assets/<resource>:

• Document templates
• Configuration templates
• Schema files

Step 6: Validate

python scripts/quick_validate_skill.py <skill-path>

Creating a Skill from Documentation

When building a skill from external docs, use the autonomous ingestion workflow:

Phase 1: Scaffold

1. Create skill folder with SKILL.md skeleton
2. Create plan.md for progress tracking
3. Create references/ directory

Phase 2: Build Queue

For each doc link:

• Fetch the page
• Extract internal doc links (avoid nav duplicates)
• Prioritize: concepts → API → operations → troubleshooting

Phase 3: Ingest Loop

For each page:

1. Fetch one page
2. Create references/<topic>.md with actionable summary
3. Update plan.md checkbox
4. Update SKILL.md if it adds a useful recipe/rule

Do not ask user after each page — continue autonomously.

Phase 4: Finalize

• Review SKILL.md for completeness
• Ensure practical recipes, not docs mirror
• plan.md may be deleted manually after ingestion

Critical Prohibitions

• Do NOT copy large verbatim chunks from vendor docs (summarize in own words)
• Do NOT write skills in languages other than English
• Do NOT include project-specific secrets, paths, or assumptions
• Do NOT keep SKILL.md over 500 lines
• Do NOT skip name validation (must match folder name)
• Do NOT use poor descriptions that lack trigger keywords
• Do NOT omit product version when creating skills from documentation

Version Tracking

When creating or updating a skill from external documentation:

1. Add version field in frontmatter for product version:

   ---
   name: my-skill
   description: "..."
   version: "1.2.3"
   ---
   

2. Optionally add release_date if known:

   ---
   name: my-skill
   description: "..."
   version: "1.2.3"
   release_date: "2025-01-21"
   ---
   

3. Create README.md with:

   • Skill overview (1-2 sentences)
   • Usage section (when to use)
   • Links section (standardized format)

README.md Links section format:

## Links

- [Documentation](https://example.com/docs)
- [Changelog](https://example.com/changelog)
- [GitHub](https://github.com/org/repo)
- [npm](https://www.npmjs.com/package/name)

Include only applicable links. Order: Documentation → Changelog/Releases → GitHub → Package registry.

Example frontmatter:

---
name: turso
description: "Turso embedded SQLite database..."
version: "0.4.0"
release_date: "2025-01-05"
---

This helps track when the skill was last updated and against which product version.

Validation Checklist

• name matches folder name
• name is 1-64 chars, lowercase, no --
• description is 1-1024 chars, includes keywords
• SKILL.md under 500 lines
• Documentation in references/, templates in assets/
• All text in English

Scripts

Script	Purpose
init_skill.py	Scaffold new Agent Skill (agentskills.io)
init_copilot_asset.py	Scaffold Copilot-specific assets (instructions, agents)
quick_validate_skill.py	Validate skill structure
package_skill.py	Package skill into distributable zip

Links

• Specification: references/specification.md
• Advanced Features: references/advanced-features.md
• SKILL.md Templates: assets/skill-templates.md
• Docs Ingestion: references/docs-ingestion.md
• Official spec: https://agentskills.io/specification
• Claude Code skills: https://code.claude.com/docs/en/skills