Tool Tailor — Development skill for Claude Code

ToolTailor

ToolTailor is a focused Ruby gem that converts Ruby methods into JSON schemas for OpenAI and Anthropic tool calling APIs.

Philosophy

ToolTailor is designed as a lightweight building block, not a full framework. It has a single purpose: to convert your existing Ruby methods with YARD documentation into tool schemas for AI tool calling. It doesn't implement the actual API calls or handle responses - it's the glue that helps you expose your existing code to AI systems with minimal effort.

Key principles:

• Do one thing well: Convert methods to JSON schemas
• Leverage existing code: Use YARD documentation you already have
• Minimal dependencies: Just YARD and standard libraries
• Composable: Works with any API client of your choice
• Extensible tags: Custom YARD tags for array items, enums, and more

Installation

Add this line to your application's Gemfile:

gem 'tool_tailor'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install tool_tailor

Usage

ToolTailor converts Ruby methods to JSON schemas:

Converting Methods

class WeatherService
  # Get the current weather in a given location.
  #
  # @param location [String] The city and state, e.g., San Francisco, CA.
  # @param unit [String] The temperature unit to use. Infer this from the user's location.
  # @values unit ["Celsius", "Fahrenheit"]
  # @param historical_data [Array] Optional array of previous weather readings
  # @items_type historical_data Object
  # @min_items historical_data 1
  # @max_items historical_data 5
  def get_current_temperature(location:, unit:, historical_data: nil)
    # Function implementation goes here
  end
end

# Convert an instance method
schema = ToolTailor.convert(WeatherService.instance_method(:get_current_temperature))

# Using to_json_schema on an unbound method
schema = WeatherService.instance_method(:get_current_temperature).to_json_schema

# Using to_json_schema on a bound me