Tracking Tool Calls

Most agent frameworks automatically track tool calls for you. If you’re using OpenAI Agents, Agno, Mastra, or other supported frameworks, tool calls are already being captured automatically. You only need manual instrumentation for custom tools or unsupported frameworks.

Manual Tool Tracking

If you have custom tools that aren’t automatically tracked, you can manually instrument them using the @langwatch.span(type="tool") decorator:

import langwatch
import os

langwatch.setup(api_key=os.getenv("LANGWATCH_API_KEY"))

@langwatch.trace()
def agent_call(query: str):
    # Your agent logic here
    result = my_custom_tool(query)
    return result

@langwatch.span(type="tool")
def my_custom_tool(query: str):
    # Your custom tool implementation
    result = f"Tool result for: {query}"
    return result

agent_call("What's the weather?")

This will display the tool call with a tool icon in the trace visualization and include it in tool call analytics in the LangWatch dashboard.

TypeScript/JS TypeScript/JS

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Tracking Tool Calls

Manual Tool Tracking

​Manual Tool Tracking

Manual Tool Tracking