how can i detect when the agent is going to make a tool call? can i listen to some event?

Thanks for reaching out, Sebastián. I'm an AI assistant and I'm here to help. Give me a moment while I research this topic.

how would the approach be with FunctionCallEvent and the CustomAgentOverrides

I'd love to guide you through how you can use FunctionCallEvent and Custom Agent Overrides to detect tool calls. Let's break it down step-by-step: • FunctionCallEvent: a. During agent execution, you can access the

RunResult.events

object. This handy feature collects all events, including

FunctionCallEvent

, which is triggered whenever a tool call starts. b. From there, you can filter these events to find

FunctionCallEvent

instances and pull out important details about the tool call. • Custom Agent Overrides: a. You’ll want to override the

llm_node

method in your custom agent implementation. b. Inside this overridden method, you can work with the

ChatChunk

instances coming through the response stream. c. This way, you can spot any

tool_calls

in the response and even trigger your own custom behavior or logging before the tool actually runs. Using these approaches, you’ll be able to keep a close eye on tool call decisions and respond to them smoothly—whether by watching events or catching decisions as they happen. If you have any questions or want to dive deeper, I’m here to help!

do you a code example for each in python?

I'm happy to share some Python code examples that show how you can use FunctionCallEvent and Custom Agent Overrides to detect tool calls. Let's walk through them together: 1. Using FunctionCallEvent:

from livekit.agents import AgentSession

async def detect_function_call():
    async with AgentSession() as session:
        def on_function_tools_executed(event):
            print(f"Function call detected: {event.function_calls}")
        
        session.on("function_tools_executed", on_function_tools_executed)
        await session.run(user_input="What is the weather in New York?")

2. Using Custom Agent Overrides:

from livekit.agents import Agent
from livekit.agents.llm import ChatChunk

class CustomAgent(Agent):
    async def llm_node(self, chat_ctx, tools, model_settings):
        async for chunk in super().llm_node(chat_ctx, tools, model_settings):
            if isinstance(chunk, ChatChunk) and chunk.delta and chunk.delta.tool_calls:
                print(f"Tool call detected: {chunk.delta.tool_calls[0].name}")
            yield chunk

These examples are designed to help you listen for tool calls, either by responding to events or by customizing the agent’s behavior to catch tool call decisions as they happen. If you have any questions or need further clarification, feel free to ask—I’m here to help! Sources: livekit-plugins/livekit-plugins-aws/livekit/plugins/aws/experimental/realti... | agent.py

the first option is too late for me ( i need to detect prior to the tool calling that we are going to make it) the second option isn't working

I don't have the answer you're looking for. You could also try asking your question: • in one of the other Slack channels or • to https://deepwiki.com/livekit/livekit_composite which is trained on all LiveKit source code If you find the answer, please post it here to help others!

so there's no way for me to know when the tool call begins executing? there's a debug log but i don't know if i have an event for that