Creating Skills

Build your own composable skill that works with the entire ecosystem.

Quick Start

Use the Skill Creator meta-skill:

/create-skill

Or create manually following this guide.

Skill Structure

skills/
  my-skill/
    SKILL.md          # Required: the skill definition
    references/       # Optional: deep-dive content
      detail.md

SKILL.md Template

Every skill starts with YAML frontmatter:

---
name: my-skill
description: >
  What this skill does. When to use it. Specific triggers.
  Must be under 1000 characters.
domain: voice | density | craft | process | content
composable: true
yields_to: [list of domain types]
---

# My Skill

[Skill instructions here]

Frontmatter Fields

Field	Required	Description
name	Yes	Kebab-case identifier
description	Yes	What it does + triggers. Under 1000 chars
domain	Yes	One of: voice, density, craft, process, content
composable	Yes	true if it works with other skills
yields_to	Yes	Domain types this skill defers to
scope	No	e.g., "responses" for density skills

Domain Selection

Choose the right domain for your skill:

Domain	Controls	Examples
Voice	Tone, vocabulary, personality	Writing styles, personas
Density	Token count, verbosity	Compression, expansion
Craft	Visual design, code quality	UI/UX, code standards
Process	Workflow, templates, structure	Reports, plans, presentations
Content	Substance being produced	Documentation, research, learning

Composition Contract

Your skill MUST follow these rules:

1. Input Agnosticism

Accept output from ANY other skill. Don't assume raw user text.

2. Domain Respect

Never modify aspects outside your domain.

3. Marker Preservation

Preserve structured output from upstream skills (tables, code blocks, frontmatter).

4. Signal Emission

In multi-skill contexts, state which domain you're handling.

5. Graceful Degradation

If conflicts arise, apply precedence rules and note what was deferred.

Writing Effective Triggers

In your description field, include specific trigger phrases:

description: >
  Ultra-terse communication mode. Cuts token usage 30-95%.
  Use when user says "caveman mode", "talk like caveman",
  "less tokens", "be brief", or invokes /caveman.

Adding References

For complex skills, add a references/ directory:

my-skill/
  SKILL.md
  references/
    deep-dive.md
    examples.md
    patterns.md

Reference files are supplementary — the skill must work without them, but they provide depth when needed.

Testing Your Skill

1. Install locally: npx skills-for-agents install --project
2. Test standalone: invoke your skill directly
3. Test composition: combine with 2-3 other skills
4. Test conflicts: try with skills in the same domain
5. Check domain respect: verify it doesn't bleed into other domains

Submitting

1. Follow the Contributing Guide
2. Ensure SIP compliance (frontmatter + composition contract)
3. Include examples in your SKILL.md
4. Add a row to SIP's Known Issues section if you found gaps