Skill Maker

Create skills that follow the agentskills.io specification. This skill provides a structured workflow for gathering requirements, scaffolding the skill structure, and validating the result.

A skill is a directory containing a SKILL.md file with YAML frontmatter and Markdown instructions. Skills extend agent capabilities with specialized knowledge, workflows, and bundled resources.

Skill Creation Workflow

Follow these four phases in order:

Phase 1: Requirements Gathering

Before writing any code, understand what the skill needs to do. Use the interactive questions in the next section to gather:

• The task or workflow the skill enables
• Concrete usage examples (what users will say)
• Required resources (scripts, references, assets)
• Trigger phrases for the description

Phase 2: Planning

With requirements gathered, plan the skill structure:

1. Choose a name (lowercase, hyphens, max 64 chars, matches folder)
2. Draft the description (what + when + keywords, max 1024 chars)
3. Decide which optional directories are needed:
   • scripts/ - Executable code for repetitive/deterministic tasks
   • references/ - Documentation loaded as needed
   • assets/ - Templates, images, data files for output
4. Outline the SKILL.md body sections

Use assets/planning-template.md for structured planning.

Phase 3: Scaffolding

Create the skill structure using the scaffold script:

deno run --allow-write --allow-read scripts/scaffold.ts \
  --name "my-skill" \
  --description "What this skill does and when to use it." \
  --path "./skills/domain/" \
  --with-scripts \
  --with-references

This creates:

my-skill/
├── SKILL.md           # Starter template with frontmatter
├── scripts/           # If --with-scripts
└── references/        # If --with-references

Then edit the generated SKILL.md to add instructions.

Phase 4: Validation

Validate the completed skill:

deno run --allow-read --allow-run scripts/validate-skill.ts ./path/to/skill

The validator checks:

• Frontmatter validity (name, description constraints)
• Name matches directory name
• Line count (warns if >500 lines)
• Referenced files exist
• Description includes trigger phrases

Fix any issues and re-validate.

Quick Start

To create a minimal skill immediately:

1. Create the directory: mkdir -p skills/domain/my-skill
2. Copy the template: cp assets/skill-md-template.md skills/domain/my-skill/SKILL.md
3. Edit the SKILL.md frontmatter and body
4. Validate: deno run --allow-read --allow-run scripts/validate-skill.ts ./skills/domain/my-skill

Interactive Requirements Gathering

When a user requests a new skill, ask these questions:

Understanding the Task

• "What task or workflow should this skill enable?"
• "Can you give 2-3 concrete examples of how this skill would be used?"
• "What would a user say that should trigger this skill?"

Identifying Resources

• "Will this skill need executable scripts for repetitive tasks?"
• "Is there reference documentation the skill should include?"
• "Are there templates or assets the skill needs to produce output?"

Defining Scope

• "What should this skill NOT handle? (Out of scope)"
• "Are there related skills this should connect to?"

Drafting the Description

Based on gathered information, draft a description following this pattern:

"[What the skill does]. This skill should be used when the user asks to [trigger phrase 1], [trigger phrase 2], [trigger phrase 3], or [scenario]. Keywords: [relevant terms]."

Key Principles

Progressive Disclosure

Structure skills for efficient context usage:

Keep SKILL.md under 500 lines. Move detailed content to references/.

Strong Trigger Descriptions

Write descriptions in third person with specific phrases:

# Good
description: "This skill should be used when the user asks to 'create a PDF',
  'extract text from PDF', 'merge PDFs', or mentions PDF processing."

# Bad
description: "Helps with PDFs."

Imperative Writing Style

Write instructions in imperative form, not second person:

# Good
Run the validation script before committing changes.
Configure the API key in the environment.

# Bad
You should run the validation script.
You need to configure the API key.

Scripts Reference

scaffold.ts

Creates skill folder structure and starter files.

deno run --allow-write --allow-read scripts/scaffold.ts \
  --name "skill-name" \
  --description "Description text" \
  --path "./target/directory/" \
  [--with-scripts] [--with-references] [--with-assets]

Options:

• --name (required): Skill name (validated for format)
• --description (required): Initial description
• --path (required): Parent directory for the skill
• --with-scripts: Create scripts/ directory
• --with-references: Create references/ directory
• --with-assets: Create assets/ directory

validate-skill.ts

Validates a skill against the agentskills.io specification.

deno run --allow-read --allow-run scripts/validate-skill.ts ./path/to/skill

Performs checks beyond the basic spec:

• Calls skills-ref validate if available
• Warns on large files (>500 lines)
• Checks for referenced file existence
• Detects second-person language patterns

Additional Resources

Reference Files

For detailed guidance, consult:

• references/spec-quick-reference.md - Condensed agentskills.io specification
• references/progressive-disclosure.md - Content organization strategies
• references/examples-gallery.md - Annotated examples of well-structured skills

Asset Files

Templates for skill creation:

• assets/skill-md-template.md - Complete SKILL.md starter template
• assets/planning-template.md - Requirements gathering worksheet

External Resources

• agentskills.io specification
• skills-ref validation tool