{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Agent and Agent Runtime\n",
    "\n",
    "In this and the following section, we focus on the core concepts of AutoGen:\n",
    "agents, agent runtime, messages, and communication.\n",
    "You will not find any AI models or tools here, just the foundational\n",
    "building blocks for building multi-agent applications."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "An agent in AutoGen is an entity defined by the base class {py:class}`autogen_core.base.BaseAgent`.\n",
    "It has a unique identifier of the type {py:class}`autogen_core.base.AgentId`,\n",
    "a metadata dictionary of the type {py:class}`autogen_core.base.AgentMetadata`,\n",
    "and method for handling messages {py:meth}`autogen_core.base.BaseAgent.on_message`.\n",
    "\n",
    "An agent runtime is the execution environment for agents in AutoGen.\n",
    "Similar to the runtime environment of a programming language,\n",
    "an agent runtime provides the necessary infrastructure to facilitate communication\n",
    "between agents, manage agent lifecycles, enforce security boundaries, and support monitoring and\n",
    "debugging.\n",
    "For local development, developers can use {py:class}`~autogen_core.application.SingleThreadedAgentRuntime`,\n",
    "which can be embedded in a Python application.\n",
    "\n",
    "```{note}\n",
    "Agents are not directly instantiated and managed by application code.\n",
    "Instead, they are created by the runtime when needed and managed by the runtime.\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Implementing an Agent\n",
    "\n",
    "To implement an agent, the developer must subclass the {py:class}`~autogen_core.base.BaseAgent` class\n",
    "and implement the {py:meth}`~autogen_core.base.BaseAgent.on_message` method.\n",
    "This method is invoked when the agent receives a message. For example,\n",
    "the following agent handles a simple message type and prints the message it receives:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "from dataclasses import dataclass\n",
    "\n",
    "from autogen_core.base import AgentId, BaseAgent, MessageContext\n",
    "\n",
    "\n",
    "@dataclass\n",
    "class MyMessageType:\n",
    "    content: str\n",
    "\n",
    "\n",
    "class MyAgent(BaseAgent):\n",
    "    def __init__(self) -> None:\n",
    "        super().__init__(\"MyAgent\")\n",
    "\n",
    "    async def on_message(self, message: MyMessageType, ctx: MessageContext) -> None:\n",
    "        print(f\"Received message: {message.content}\")  # type: ignore"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This agent only handles `MyMessageType` messages. \n",
    "To handle multiple message types, developers can subclass the {py:class}`~autogen_core.components.RoutedAgent` class\n",
    "which provides an easy-to use API to implement different message handlers for different message types.\n",
    "See the next section on [message and communication](./message-and-communication.ipynb)."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Registering Agent Type\n",
    "\n",
    "To make agents available to the runtime, developers can use the\n",
    "{py:meth}`~autogen_core.base.BaseAgent.register` class method of the\n",
    "{py:class}`~autogen_core.base.BaseAgent` class.\n",
    "The process of registration associates an agent type, which is uniquely identified by a string, \n",
    "and a factory function\n",
    "that creates an instance of the agent type of the given class.\n",
    "The factory function is used to allow automatic creation of agent instances \n",
    "when they are needed.\n",
    "\n",
    "Agent type ({py:class}`~autogen_core.base.AgentType`) is not the same as the agent class. In this example,\n",
    "the agent type is `AgentType(\"my_agent\")` and the agent class is the Python class `MyAgent`.\n",
    "The factory function is expected to return an instance of the agent class \n",
    "on which the {py:meth}`~autogen_core.base.BaseAgent.register` class method is invoked.\n",
    "Read [Agent Identity and Lifecycles](../core-concepts/agent-identity-and-lifecycle.md)\n",
    "to learn more about agent type and identity.\n",
    "\n",
    "```{note}\n",
    "Different agent types can be registered with factory functions that return \n",
    "the same agent class. For example, in the factory functions, \n",
    "variations of the constructor parameters\n",
    "can be used to create different instances of the same agent class.\n",
    "```\n",
    "\n",
    "To register an agent type with the \n",
    "{py:class}`~autogen_core.application.SingleThreadedAgentRuntime`,\n",
    "the following code can be used:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "AgentType(type='my_agent')"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from autogen_core.application import SingleThreadedAgentRuntime\n",
    "\n",
    "runtime = SingleThreadedAgentRuntime()\n",
    "await MyAgent.register(runtime, \"my_agent\", lambda: MyAgent())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Once an agent type is registered, we can send a direct message to an agent instance\n",
    "using an {py:class}`~autogen_core.base.AgentId`.\n",
    "The runtime will create the instance the first time it delivers a\n",
    "message to this instance."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Received message: Hello, World!\n"
     ]
    }
   ],
   "source": [
    "agent_id = AgentId(\"my_agent\", \"default\")\n",
    "runtime.start()  # Start processing messages in the background.\n",
    "await runtime.send_message(MyMessageType(\"Hello, World!\"), agent_id)\n",
    "await runtime.stop()  # Stop processing messages in the background."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "```{note}\n",
    "Because the runtime manages the lifecycle of agents, an {py:class}`~autogen_core.base.AgentId`\n",
    "is only used to communicate with the agent or retrieve its metadata (e.g., description).\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Running the Single-Threaded Agent Runtime\n",
    "\n",
    "The above code snippet uses `runtime.start()` to start a background task\n",
    "to process and deliver messages to recepients' message handlers.\n",
    "This is a feature of the\n",
    "local embedded runtime {py:class}`~autogen_core.application.SingleThreadedAgentRuntime`.\n",
    "\n",
    "To stop the background task immediately, use the `stop()` method:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "runtime.start()\n",
    "# ... Send messages, publish messages, etc.\n",
    "await runtime.stop()  # This will return immediately but will not cancel\n",
    "# any in-progress message handling."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "You can resume the background task by calling `start()` again.\n",
    "\n",
    "For batch scenarios such as running benchmarks for evaluating agents,\n",
    "you may want to wait for the background task to stop automatically when\n",
    "there are no unprocessed messages and no agent is handling messages --\n",
    "the batch may considered complete.\n",
    "You can achieve this by using the `stop_when_idle()` method:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "runtime.start()\n",
    "# ... Send messages, publish messages, etc.\n",
    "await runtime.stop_when_idle()  # This will block until the runtime is idle."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "You can also directly process messages one-by-one without a background task using:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "await runtime.process_next()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Other runtime implementations will have their own ways of running the runtime."
   ]
  }
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