> ## Documentation Index
> Fetch the complete documentation index at: https://arize-ax.mintlify.site/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Instrument an agent and review traces

> Instrument your application so it streams traces into Arize AX, then review the traces a live agent produces.

Instrumentation captures each step your application takes and streams it into Arize AX as traces. With a few lines of setup, every LLM call, tool invocation, and retrieval becomes visible and ready to evaluate.

## Set up tracing in Arize AX

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  <video src="https://storage.googleapis.com/arize-assets/doc-images/Learn/episode%203.mp4" controls />
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What tracing requires and how instrumentation captures each step of your application.

## Instrument a live agent and view its traces

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  <video src="https://storage.googleapis.com/arize-assets/doc-images/Learn/episode%204.mp4" controls />
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Instrument a working agent end to end and review its traces as they arrive in Arize AX.

## Up next

<Card title="Create and validate evaluators" href="/ax/learn/getting-started-with-ax/observe-and-evaluate" icon="scale-balanced">
  Define success criteria and build code and LLM-as-a-judge evaluators you can trust.
</Card>