Class: Google::ADK::LlmAgent

Inherits:
BaseAgent show all
Defined in:
lib/google/adk/agents/llm_agent.rb

Overview

LLM-powered agent that can use tools and interact with language models

Constant Summary

Constants inherited from BaseAgent

BaseAgent::AGENT_NAME_REGEX

Instance Attribute Summary collapse

Attributes inherited from BaseAgent

#after_agent_callback, #before_agent_callback, #description, #name, #parent_agent, #sub_agents

Instance Method Summary collapse

Methods inherited from BaseAgent

#clone, #find_agent, #find_sub_agent, from_config, #run_live

Constructor Details

#initialize(name:, model: nil, instructions: nil, description: nil, tools: [], sub_agents: [], include_from_children: [], inherit_parent_model: false, before_model_callback: nil, after_model_callback: nil, before_tool_callback: nil, after_tool_callback: nil, before_agent_callback: nil, after_agent_callback: nil, code_executor: nil, planner: nil) ⇒ LlmAgent

Initialize an LLM agent

Parameters:

  • name (String) —

    Agent name

  • model (String, nil) (defaults to: nil) —

    Model name (e.g., “gemini-2.0-flash”)

  • instructions (String) (defaults to: nil) —

    System instructions (can include variables)

  • description (String) (defaults to: nil) —

    Agent description

  • tools (Array) (defaults to: []) —

    Tools available to the agent

  • sub_agents (Array<BaseAgent>) (defaults to: []) —

    Child agents

  • include_from_children (Array<String>) (defaults to: []) —

    What to include from children

  • inherit_parent_model (Boolean) (defaults to: false) —

    Whether to inherit parent’s model

  • before_model_callback (Proc) (defaults to: nil) —

    Called before model invocation

  • after_model_callback (Proc) (defaults to: nil) —

    Called after model invocation

  • before_tool_callback (Proc) (defaults to: nil) —

    Called before tool execution

  • after_tool_callback (Proc) (defaults to: nil) —

    Called after tool execution

  • code_executor (Object) (defaults to: nil) —

    Optional code executor

  • planner (Object) (defaults to: nil) —

    Optional planner

Raises:

  • (ArgumentError) —

    If model is required but not provided



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# File 'lib/google/adk/agents/llm_agent.rb', line 34

def initialize(name:, model: nil, instructions: nil, description: nil,
               tools: [], sub_agents: [], include_from_children: [],
               inherit_parent_model: false,
               before_model_callback: nil, after_model_callback: nil,
               before_tool_callback: nil, after_tool_callback: nil,
               before_agent_callback: nil, after_agent_callback: nil,
               code_executor: nil, planner: nil)
  super(
    name: name,
    description: description,
    sub_agents: sub_agents,
    before_agent_callback: before_agent_callback,
    after_agent_callback: after_agent_callback
  )

  raise ArgumentError, "model is required" if model.nil? && !inherit_parent_model

  @model = model
  @instructions = instructions
  @tools = tools
  @include_from_children = include_from_children
  @inherit_parent_model = inherit_parent_model
  @before_model_callback = before_model_callback
  @after_model_callback = after_model_callback
  @before_tool_callback = before_tool_callback
  @after_tool_callback = after_tool_callback
  @code_executor = code_executor
  @planner = planner
end

Instance Attribute Details

#after_model_callback ⇒ Object (readonly)

Returns the value of attribute after_model_callback.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def after_model_callback
  @after_model_callback
end

#after_tool_callback ⇒ Object (readonly)

Returns the value of attribute after_tool_callback.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def after_tool_callback
  @after_tool_callback
end

#before_model_callback ⇒ Object (readonly)

Returns the value of attribute before_model_callback.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def before_model_callback
  @before_model_callback
end

#before_tool_callback ⇒ Object (readonly)

Returns the value of attribute before_tool_callback.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def before_tool_callback
  @before_tool_callback
end

#code_executor ⇒ Object (readonly)

Returns the value of attribute code_executor.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def code_executor
  @code_executor
end

#include_from_children ⇒ Object (readonly)

Returns the value of attribute include_from_children.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def include_from_children
  @include_from_children
end

#inherit_parent_model ⇒ Object (readonly)

Returns the value of attribute inherit_parent_model.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def inherit_parent_model
  @inherit_parent_model
end

#instructions ⇒ Object (readonly)

Returns the value of attribute instructions.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def instructions
  @instructions
end

#model ⇒ Object (readonly)

Returns the value of attribute model.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def model
  @model
end

#planner ⇒ Object (readonly)

Returns the value of attribute planner.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def planner
  @planner
end

#tools ⇒ Object (readonly)

Returns the value of attribute tools.



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# File 'lib/google/adk/agents/llm_agent.rb', line 13

def tools
  @tools
end

Instance Method Details

#canonical_instructions(context) ⇒ String

Get canonical instructions with variables interpolated

Parameters:

  • context (Context) —

    Current context

Returns:

  • (String) —

    Processed instructions



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# File 'lib/google/adk/agents/llm_agent.rb', line 82

def canonical_instructions(context)
  return "" unless @instructions

  # Simple variable interpolation from state
  processed = @instructions.dup
  context.state.each do |key, value|
    processed.gsub!("{#{key}}", value.to_s)
  end
  processed
end

#canonical_model ⇒ String

Get the canonical model to use

Returns:

  • (String) —

    Model name

Raises:



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# File 'lib/google/adk/agents/llm_agent.rb', line 68

def canonical_model
  return @model if @model

  if @inherit_parent_model && @parent_agent&.respond_to?(:canonical_model)
    return @parent_agent.canonical_model
  end

  raise ConfigurationError, "No model specified for agent #{@name}"
end

#canonical_tools ⇒ Array<BaseTool>

Get canonical tools (converted to proper tool objects)

Returns:



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# File 'lib/google/adk/agents/llm_agent.rb', line 96

def canonical_tools
  @tools.map do |tool|
    case tool
    when BaseTool
      tool
    when BaseAgent
      AgentTool.new(agent: tool)
    else
      # Assume it's a callable (proc/method)
      FunctionTool.new(
        name: tool_name_from_callable(tool),
        description: "Function tool",
        callable: tool
      )
    end
  end
end

#run_async(message, context: nil) {|Event| ... } ⇒ Object

Implementation of async run

Parameters:

  • message (String) —

    User message

  • context (InvocationContext) (defaults to: nil) —

    Invocation context

Yields:

  • (Event) —

    Events during execution



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# File 'lib/google/adk/agents/llm_agent.rb', line 119

def run_async(message, context: nil)
  Enumerator.new do |yielder|
    begin
      # Initialize Gemini client
      client = GeminiClient.new
      
      # Build simple message for now
      messages = [{ role: "user", content: message }]
      
      # Get tools and convert to Gemini format
      tools = canonical_tools.map(&:to_gemini_schema)
      
      # Create more forceful system instruction for tools
      system_instruction = build_tool_aware_instructions(context, tools)
      
      # Call Gemini API with tools
      response = client.generate_content(
        model: canonical_model,
        messages: messages,
        tools: tools.empty? ? nil : tools,
        system_instruction: system_instruction
      )
      
      # Process response
      if response.dig("candidates", 0, "content", "parts")
        parts = response["candidates"][0]["content"]["parts"]
        
        parts.each do |part|
          if part["text"]
            # Regular text response
            event = Event.new(
              invocation_id: context&.invocation_id || "inv-#{SecureRandom.uuid}",
              author: @name,
              content: part["text"]
            )
            yielder << event
            context&.add_event(event) if context
            
          elsif part["functionCall"]
            # Tool call - execute and get result
            function_call = part["functionCall"]
            tool_name = function_call["name"]
            tool_args = function_call["args"] || {}
            
            # Execute the tool
            tool_result = execute_tool_call(tool_name, tool_args, yielder, context)
            
            # Call LLM again with tool result
            tool_messages = messages + [
              {
                role: "model",
                parts: [{ functionCall: function_call }]
              },
              {
                role: "function", 
                parts: [{
                  functionResponse: {
                    name: tool_name,
                    response: tool_result
                  }
                }]
              }
            ]
            
            follow_up_response = client.generate_content(
              model: canonical_model,
              messages: tool_messages,
              system_instruction: system_instruction
            )
            
            if follow_up_response.dig("candidates", 0, "content", "parts", 0, "text")
              final_text = follow_up_response["candidates"][0]["content"]["parts"][0]["text"]
              event = Event.new(
                invocation_id: context&.invocation_id || "inv-#{SecureRandom.uuid}",
                author: @name,
                content: final_text
              )
              yielder << event
              context&.add_event(event) if context
            end
          end
        end
      else
        # Fallback response
        event = Event.new(
          invocation_id: context&.invocation_id || "inv-#{SecureRandom.uuid}",
          author: @name,
          content: "I'm sorry, I couldn't process that request."
        )
        yielder << event
        context&.add_event(event) if context
      end
      
    rescue => e
      # Error handling
      puts "[DEBUG] Gemini error: #{e.message}" if ENV["DEBUG"]
      puts "[DEBUG] Backtrace: #{e.backtrace.first(3).join(', ')}" if ENV["DEBUG"]
      
      event = Event.new(
        invocation_id: context&.invocation_id || "inv-#{SecureRandom.uuid}",
        author: @name,
        content: "Error calling Gemini API: #{e.message}. Please check your GEMINI_API_KEY."
      )
      yielder << event
      context&.add_event(event) if context
    end
  end
end