ajoslin

skill-creator

Create effective skills for OpenCode agents. Load FIRST before writing any SKILL.md. Provides required format, naming conventions, progressive disclosure patterns, and validation. Use when building, reviewing, or debugging skills.

ajoslin 23 6 Updated 3mo ago

Resources

4
GitHub

Install

npx skillscat add ajoslin/dot/skill-creator

Install via the SkillsCat registry.

SKILL.md

Building Skills

Skills extend agent capabilities with specialized knowledge, workflows, and tools.

Quick Start

Minimal viable skill in 30 seconds:

mkdir my-skill && cat > my-skill/SKILL.md << 'EOF'
---
name: my-skill
description: Does X when Y happens. Use for Z tasks.
---

# My Skill

Instructions go here.
EOF

Place in .opencode/skills/ (project) or ~/.config/opencode/skills/ (global).

Skill Type Decision Tree

What are you building?
├─ Instructions only → Simple skill (SKILL.md only)
│   Example: code-review guidelines, commit message format
│
├─ Domain knowledge → Reference-heavy skill (+ references/)
│   Example: API docs, database schemas, company policies
│
├─ Repeatable automation → Script-heavy skill (+ scripts/)
│   Example: PDF processing, data validation, file conversion
│
├─ Complex multi-step workflow → Multi-file skill (all directories)
│   Example: release process, deployment pipeline
│
└─ Large platform → Progressive skill
    Example: AWS, GCP, Cloudflare (60+ products)

When to Create a Skill

Create a skill when:

  • Same instructions repeated across conversations
  • Domain knowledge model lacks (schemas, internal APIs, company policies)
  • Workflow requires 3+ steps with specific order
  • Code rewritten repeatedly for same task
  • Team needs shared procedural knowledge

When NOT to Create a Skill

Scenario Do Instead
Single-use instructions AGENTS.md or inline in conversation
Model already knows domain Don't add redundant context
< 3 steps, no reuse Inline instructions
Highly variable workflow Higher-freedom guidelines
Just want to store files Use regular directories

Reading Order

Task Files to Read
New skill from scratch anatomy.md → frontmatter.md
Optimize existing skill progressive-disclosure.md
Add scripts/resources bundled-resources.md
Find skill pattern patterns.md
Debug/fix skill gotchas.md

In This Reference

File Purpose
anatomy.md Skill directory structures
frontmatter.md YAML spec, naming, validation
progressive-disclosure.md Token-efficient design
bundled-resources.md scripts/, references/, assets/
patterns.md Real-world skill patterns
gotchas.md Common mistakes + fixes

Scripts

Script Purpose
scripts/init_skill.sh Scaffold new skill
scripts/validate_skill.sh Validate skill structure
scripts/package_skill.sh Create distributable zip

Pre-Flight Checklist

Before using a skill:

  • SKILL.md starts with --- (line 1, no blank lines)
  • name: field present, matches directory name
  • description: includes what + when to use
  • Closing --- after frontmatter
  • SKILL.md under 200 lines (use references/ for more)
  • All internal links resolve

Run: ./scripts/validate_skill.sh ./my-skill

Skill Locations

Priority Location
1 .opencode/skills/<name>/ (project)
2 ~/.config/opencode/skills/<name>/ (global)
3 .claude/skills/<name>/ (Claude-compat)

Discovery walks up from CWD to git root. First-wins for duplicate names.

See Also