Adds the ability to define more complex param schemas, while retaining the existing simple methods + bump version to 1.3 since this is kind of a major feature.

Author: jayelkaake

.gitignore

@@ -47,8 +47,8 @@ build-iPhoneSimulator/
 # for a library or gem, you might want to ignore these files since the code is
 # intended to run in multiple environments; otherwise, check them in:
 Gemfile.lock
-# .ruby-version
-# .ruby-gemset
+.ruby-version
+.ruby-gemset
 
 # unless supporting rvm < 1.11.0 or doing something fancy, ignore this:
 .rvmrc
@@ -57,3 +57,4 @@ Gemfile.lock
 # .rubocop-https?--*
 
 repomix-output.*
+/.idea/

docs/guides/tools.md

@@ -53,26 +53,60 @@ class Weather < RubyLLM::Tool
   param :longitude, desc: "Longitude (e.g., 13.4050)"
 
   def execute(latitude:, longitude:)
+    puts "Requested weather for #{location[:city]}, #{location[:country]}" if location
+    puts "Use unit: #{unit}" if unit
+    
     url = "https://api.open-meteo.com/v1/forecast?latitude=#{latitude}&longitude=#{longitude}&current=temperature_2m,wind_speed_10m"
 
     response = Faraday.get(url)
-    data = JSON.parse(response.body)
+    JSON.parse(response.body)
   rescue => e
     { error: e.message }
   end
 end
 ```
 
-### Tool Components
+### 1. Inherit from `RubyLLM::Tool`.
+**Inheritance:** Must inherit from `RubyLLM::Tool`.
+### 2. Use the **`description`** to describe the tool.
+Use the **`description`** class method defining what the tool does. Crucial for the AI model to understand its purpose. Keep it clear and concise.
+
+### 3. Define params with **`param`**
+Define parameters with **`param`** class method.
+
+* The first param is always the name of the parameter.
+* The remaining arguments are a hash representing the JSON schema of the parameter.
+  * Note 1: The root `required:` option isn't included in the schema.
+    * It specifies whether the AI *must* provide this parameter when calling the tool. 
+    * It defaults to `true` (required)
+    * Set to `false` for optional parameters and provide a default value in your `execute` method signature.
+  * Note 2: `desc:` is automatically converted to `description:` in the schema. 
+    * Only root level `desc:` is supported. 
+    * If using more complex schemas, use `description:` instead.
+
+#### Short form example:
+Define simple parameters with the shorthand format:
+```ruby
+  param :latitude, desc: "Latitude (e.g., 52.5200)"
+```
+
+#### More complex examples:
+More complex JSON schemas are supported simply by defining them here as well:
+```ruby
+  param :longitude, type: 'number', description: "Longitude (e.g., 13.4050)", required: true
+
+  param :unit, type: :string, enum: %w[f c], description: "Temperature unit (e.g., celsius, fahrenheit)", required: false
+
+  param :location, type: :object, desc: "Country and city where weather is requested.", required: false, properties: {
+    country: { type: :string, description: "Full name of the country." },
+    city: { type: :string, description: "Full name of the city." }
+  }
+```
+Remember, `required:` at the root is not part of the JSON schema and automatically removed before sending to the LLM API.
+Also, `desc` at the root level is converted to `description`.
 
-1.  **Inheritance:** Must inherit from `RubyLLM::Tool`.
-2.  **`description`:** A class method defining what the tool does. Crucial for the AI model to understand its purpose. Keep it clear and concise.
-3.  **`param`:** A class method used to define each input parameter.
-    *   **Name:** The first argument (a symbol) is the parameter name. It will become a keyword argument in the `execute` method.
-    *   **`type:`:** (Optional, defaults to `:string`) The expected data type. Common types include `:string`, `:integer`, `:number` (float), `:boolean`. Provider support for complex types like `:array` or `:object` varies. Stick to simple types for broad compatibility.
-    *   **`desc:`:** (Required) A clear description of the parameter, explaining its purpose and expected format (e.g., "The city and state, e.g., San Francisco, CA").
-    *   **`required:`:** (Optional, defaults to `true`) Whether the AI *must* provide this parameter when calling the tool. Set to `false` for optional parameters and provide a default value in your `execute` method signature.
-4.  **`execute` Method:** The instance method containing your Ruby code. It receives the parameters defined by `param` as keyword arguments. Its return value (typically a String or Hash) is sent back to the AI model.
+### 3. Define `execute` method
+Define the `execute` instance method containing your Ruby code. It receives the parameters defined by `param` as keyword arguments. Its return value (typically a String or Hash) is sent back to the AI model.
 
 {: .note }
 The tool's class name is automatically converted to a snake_case name used in the API call (e.g., `WeatherLookup` becomes `weather_lookup`).
@@ -210,4 +244,4 @@ Treat any arguments passed to your `execute` method as potentially untrusted use
 *   [Chatting with AI Models]({% link guides/chat.md %})
 *   [Streaming Responses]({% link guides/streaming.md %}) (See how tools interact with streaming)
 *   [Rails Integration]({% link guides/rails.md %}) (Persisting tool calls and results)
-*   [Error Handling]({% link guides/error-handling.md %})
+*   [Error Handling]({% link guides/error-handling.md %})

lib/ruby_llm/providers/anthropic/tools.rb

@@ -53,7 +53,7 @@ def function_for(tool)
             description: tool.description,
             input_schema: {
               type: 'object',
-              properties: clean_parameters(tool.parameters),
+              properties: tool.parameters.transform_values(&:schema),
               required: required_parameters(tool.parameters)
             }
           }
@@ -79,15 +79,6 @@ def parse_tool_calls(content_block)
           }
         end
 
-        def clean_parameters(parameters)
-          parameters.transform_values do |param|
-            {
-              type: param.type,
-              description: param.description
-            }.compact
-          end
-        end
-
         def required_parameters(parameters)
           parameters.select { |_, param| param.required }.keys
         end

lib/ruby_llm/providers/gemini/tools.rb

@@ -59,19 +59,43 @@ def function_declaration_for(tool)
         end
 
         # Format tool parameters for Gemini API
+        # @param parameters [Hash{Symbol => RubyLLM::Parameter}]
+        # @return [Hash{String => String|Array|Hash|Boolean|NilClass}]
         def format_parameters(parameters)
           {
             type: 'OBJECT',
             properties: parameters.transform_values do |param|
-              {
-                type: param_type_for_gemini(param.type),
-                description: param.description
-              }.compact
+              convert_gemini_types(param.schema)
             end,
             required: parameters.select { |_, p| p.required }.keys.map(&:to_s)
           }
         end
 
+        ##
+        # Convert JSON schema types to Gemini API types
+        # @param schema [Hash]
+        def convert_gemini_types(schema)
+          schema = schema.dup
+
+          schema['type'] = param_type_for_gemini(schema['type']) if schema.key?('type')
+          schema[:type] = param_type_for_gemini(schema[:type]) if schema.key?(:type)
+
+          schema.transform_values { |schema_value| convert_schema_value(schema_value) }
+        end
+
+        ##
+        # Convert schema values to Gemini API types
+        # @param schema_value [String|Array|Hash|Boolean|NilClass]
+        def convert_schema_value(schema_value)
+          if schema_value.is_a?(Hash)
+            convert_gemini_types(schema_value.to_h)
+          elsif schema_value.is_a?(Array)
+            schema_value.map { |v| convert_gemini_types(v) }
+          else
+            schema_value
+          end
+        end
+
         # Convert RubyLLM param types to Gemini API types
         def param_type_for_gemini(type)
           case type.to_s.downcase

lib/ruby_llm/providers/openai/tools.rb

@@ -15,20 +15,13 @@ def tool_for(tool) # rubocop:disable Metrics/MethodLength
               description: tool.description,
               parameters: {
                 type: 'object',
-                properties: tool.parameters.transform_values { |param| param_schema(param) },
+                properties: tool.parameters.transform_values(&:schema),
                 required: tool.parameters.select { |_, p| p.required }.keys
               }
             }
           }
         end
 
-        def param_schema(param)
-          {
-            type: param.type,
-            description: param.description
-          }.compact
-        end
-
         def format_tool_calls(tool_calls) # rubocop:disable Metrics/MethodLength
           return nil unless tool_calls&.any?
 

lib/ruby_llm/schema.rb

@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+module RubyLLM
+  ##
+  # Schema class for defining the structure of data objects.
+  # Wraps the #Hash class
+  # @see #Hash
+  class Schema
+    delegate_missing_to :@schema
+
+    ##
+    # @param schema [Hash]
+    def initialize(schema = {})
+      @schema = deep_transform_keys_in_object(schema.to_h.dup, &:to_sym)
+    end
+
+    def [](key)
+      @schema[key.to_sym]
+    end
+
+    def []=(key, new_value)
+      @schema[key.to_sym] = deep_transform_keys_in_object(new_value, &:to_sym)
+    end
+
+    # Adds the new_value into the new_key key for every sub-schema that is of type: :object
+    # @param new_key [Symbol] The key to add to each object type.
+    # @param new_value [Boolean, String] The value to assign to the new key.
+    def add_to_each_object_type!(new_key, new_value)
+      add_to_each_object_type(new_key, new_value, @schema)
+    end
+
+    # @return [Boolean]
+    def present?
+      @schema.present? && @schema[:type].present?
+    end
+
+    private
+
+    def add_to_each_object_type(new_key, new_value, schema)
+      return schema unless schema.is_a?(Hash)
+
+      if schema[:type].to_s == :object.to_s
+        add_to_object_type(new_key, new_value, schema)
+      elsif schema[:type].to_s == :array.to_s && schema[:items]
+        schema[:items] = add_to_each_object_type(new_key, new_value, schema[:items])
+      end
+
+      schema
+    end
+
+    def add_to_object_type(new_key, new_value, schema)
+      if schema[new_key.to_sym].nil?
+        schema[new_key.to_sym] = new_value.is_a?(Proc) ? new_value.call(schema) : new_value
+      end
+
+      schema[:properties]&.transform_values! { |value| add_to_each_object_type(new_key, new_value, value) }
+    end
+
+    ##
+    # Recursively transforms keys in a hash or array to symbols.
+    # Borrowed from ActiveSupport's Hash#deep_transform_keys
+    # @param object [Object] The object to transform.
+    # @param block [Proc] The block to apply to each key.
+    # @return [Object] The transformed object.
+    def deep_transform_keys_in_object(object, &block)
+      case object
+      when Hash
+        object.each_with_object({}) do |(key, value), result|
+          result[yield(key)] = deep_transform_keys_in_object(value, &block)
+        end
+      when Array
+        object.map { |e| deep_transform_keys_in_object(e, &block) }
+      else
+        object
+      end
+    end
+  end
+end

lib/ruby_llm/tool.rb

@@ -3,15 +3,40 @@
 module RubyLLM
   # Parameter definition for Tool methods. Specifies type constraints,
   # descriptions, and whether parameters are required.
+  #
+  # @!attribute name [r]
+  #   @return [Symbol]
+  # @!attribute required [r]
+  #   @return [Boolean]
+  # @!attribute schema [r]
+  #   @return [RubyLLM::Schema]
   class Parameter
-    attr_reader :name, :type, :description, :required
+    attr_reader :name, :required, :schema
 
-    def initialize(name, type: 'string', desc: nil, required: true)
+    # If providing schema directly MAKE SURE TO USE STRING KEYS.
+    # Also note that under_scored keys are NOT automatically transformed to camelCase.
+    # @param name [Symbol]
+    # @param schema [Hash{String|Symbol => String|Array|Hash|Boolean|NilClass}, NilClass]
+    def initialize(name, required: true, **schema)
       @name = name
-      @type = type
-      @description = desc
       @required = required
+
+      @schema = Schema.new(schema)
+      @schema[:description] ||= @schema.delete(:desc) if @schema.key?(:desc)
+      @schema[:type] ||= :string
+    end
+
+    # @return [String]
+    def type
+      @schema[:type]
     end
+
+    # @return [String, NilClass]
+    def description
+      @schema[:description]
+    end
+
+    alias required? required
   end
 
   # Base class for creating tools that AI models can use. Provides a simple
@@ -39,8 +64,24 @@ def description(text = nil)
         @description = text
       end
 
-      def param(name, **options)
-        parameters[name] = Parameter.new(name, **options)
+      # Define a parameter for the tool.
+      # Examples:
+      # ```ruby
+      #   param :latitude, desc: "Latitude (e.g., 52.5200)" # Shorthand format
+      #
+      #   param :longitude, type: 'number', description: "Longitude (e.g., 13.4050)", required: false # Longer format
+      #
+      #   param :unit, type: :string, enum: %w[f c], description: "Temperature unit (e.g., celsius, fahrenheit)"
+      #
+      #   param :location, type: :object, desc: "Country and city where weather is requested.", properties: {
+      #     country: { type: :string, description: "Full name of the country." },
+      #     city: { type: :string, description: "Full name of the city." }
+      #   }
+      # ```
+      # @param name [Symbol]
+      # @param schema [Hash{String|Symbol => String|Numeric|Boolean|Hash|Array|NilClass}, NilClass]
+      def param(name, required: true, **schema)
+        parameters[name] = Parameter.new(name, required: required, **schema)
       end
 
       def parameters

lib/ruby_llm/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module RubyLLM
-  VERSION = '1.2.0'
+  VERSION = '1.3.0'
 end