how to register a rely function Issue-478

website/docs/FAQ.md

@@ -127,3 +127,34 @@ Workaround:
 2. `mkdir /home/vscode/.local/lib/python3.10/site-packages/google/colab`
 
 Explanation: Per [this gist](https://gist.github.com/defulmere/8b9695e415a44271061cc8e272f3c300?permalink_comment_id=4711478#gistcomment-4711478), linked from the official [chromadb docs](https://docs.trychroma.com/troubleshooting#sqlite), adding this folder triggers chromadb to use pysqlite3 instead of the default.
+
+## How to register a reply function
+
+(from [issue #478](https://github.com/microsoft/autogen/issues/478))
+
+You can hook in a function that is called whenever an agent receives a message
+
+Assuming you have two agents user_proxy and assistant, you can register a function with these agents that gets called with some parameters.
+
+```
+def print_messages(recipient, messages, sender, config):
+    if "callback" in config and  config["callback"] is not None:
+        callback = config["callback"]
+        callback(sender, recipient, messages[-1])
+    print(f"Messages sent to: {recipient.name} | num messages: {len(messages)}")
+    return False, None  # required to ensure the agent communication flow continues
+
+user_proxy.register_reply(
+    [autogen.Agent, None],
+    reply_func=print_messages,
+    config={"callback": None},
+)
+
+assistant.register_reply(
+    [autogen.Agent, None],
+    reply_func=print_messages,
+    config={"callback": None},
+)
+
+```
+In the above, we register a print_messages message that is called each time the agent receive a message.