Okyline Skill for Claude

A skill that turns Claude into an Okyline expert — able to create, edit, and convert Okyline schemas, a declarative, example-driven syntax for describing and validating JSON data.

Features

Full Okyline core language support:

• Example-driven: structure and types inferred from realistic example values
• Inline constraints: ranges (0..100), length {2,50}, enums ('A','B','C'), regex ~pattern~, required @, nullable ?...
• Arrays and maps: size [1,10], element validation ->, uniqueness !, pattern keys
• Custom formats $format and nomenclatures $nomenclature
• Built-in formats: $Email, $Date, $DateTime...
• Conditional directives $appliedIf, $requiredIf, $forbiddenIf...
• Expression language for computed validations $compute
• Reusable definitions with $defs and $ref (internal references)

Installation

Claude.ai

1. Go to Settings > Customize > Skills
2. Click + > Create skill and upload the ZIP file

Claude Code

Copy or extract this folder to your skills directory:

# Global (all projects)
~/.claude/skills/okyline/

# Or project-specific
.claude/skills/okyline/

OpenAI Codex CLI

Copy or extract this folder to:

~/.codex/skills/okyline/

Usage

Simply ask Claude to create an Okyline schema:

• "Create an Okyline schema for a user profile"
• "Write an okyline for an invoice with line items"
• "Generate a JSON validation schema using Okyline"

You can also provide more context:

• "Create an Okyline schema for a product with name (required, 2-100 chars), price (positive), and optional description"
• "Convert this JSON Schema to Okyline"
• "Transform this Avro schema into Okyline format"

For best results, provide a JSON example along with your existing validation rules or data specifications — Claude will translate them into Okyline constraints automatically.

Or ask questions about the language itself:

• "How do I make a field nullable in Okyline?"
• "How do I define an enum in Okyline?"
• "Explain how references work"

Claude will automatically invoke this skill when relevant.

Skill Structure

okyline-skill/
├── README.md                             # This file
├── LICENSE                               # Apache 2.0
├── SKILL.md                              # Main skill instructions
└── references/
    ├── syntax-reference.md               # Complete constraint syntax
    ├── internal-references.md            # $defs and $ref usage
    ├── conditional-directives.md         # Conditional logic
    ├── expression-language.md            # $compute expressions
    └── virtual-fields.md                 # $field virtual fields

Example

{
  "$oky": {
    "name|@ {2,50}|User name": "Alice",
    "email|@ ~$Email~": "alice@example.com",
    "age|(18..120)": 30,
    "status|@ ('ACTIVE','INACTIVE')": "ACTIVE"
  }
}

Links

• Okyline Free Resources
• Okyline Free Studio
• Okyline Java library on Maven Central
• Okyline Specification
• Agent Skills Standard

License

This skill is licensed under the Apache License 2.0.