Messages

In AutoGen AgentChat, messages facilitate communication and information exchange with other agents, orchestrators, and applications. AgentChat supports various message types, each designed for specific purposes.

Types of Messages

At a high level, messages in AgentChat can be categorized into two types: agent-agent messages and an agent’s internal events and messages.

Agent-Agent Messages

AgentChat supports many message types for agent-to-agent communication. The most common one is the ChatMessage. This message type allows both text and multimodal communication and subsumes other message types, such as TextMessage or MultiModalMessage.

For example, the following code snippet demonstrates how to create a text message, which accepts a string content and a string source:

from autogen_agentchat.messages import TextMessage

text_message = TextMessage(content="Hello, world!", source="User")

Similarly, the following code snippet demonstrates how to create a multimodal message, which accepts a list of strings or Image objects:

from io import BytesIO

import requests
from autogen_agentchat.messages import MultiModalMessage
from autogen_core import Image as AGImage
from PIL import Image

pil_image = Image.open(BytesIO(requests.get("https://picsum.photos/300/200").content))
img = AGImage(pil_image)
multi_modal_message = MultiModalMessage(content=["Can you describe the content of this image?", img], source="User")
img

The TextMessage and MultiModalMessage we have created can be passed to agents directly via the on_messages method, or as tasks given to a team run() method. Messages are also used in the responses of an agent. We will explain these in more detail in Agents and Teams.

Internal Events and Messages

AgentChat also supports the concept of inner_messages - messages that are internal to an agent. These messages are used to communicate events and information on actions within the agent itself.

Examples of these include ToolCallMessage, which indicates that a request was made to call a tool, and ToolCallResultMessage, which contains the results of tool calls.

Typically, these messages are created by the agent itself and are contained in the inner_messages field of the Response returned from on_messages. If you are building a custom agent and have events that you want to communicate to other entities (e.g., a UI), you can inlcude these in the inner_messages field of the Response. We will show examples of this in Custom Agents.

You can read about the full set of messages supported in AgentChat in the messages module.