> ## Documentation Index
> Fetch the complete documentation index at: https://arizeai-433a7140.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# 04.18.2025: Tracing for MCP client server applications

> Available in Phoenix 8.26+

<Update label="04.18.2025">
  ## Tracing For MCP Client Server Applications

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  We're excited to announce a powerful capability in the [**OpenInference**](https://github.com/Arize-ai/openinference) OSS library **`openinference-instrumentation-mcp` —** seamless OTEL context propagation for MCP clients and servers.

  ### **What's New?**

  This release introduces automatic distributed tracing for **Anthropic's Model Context Protocol (MCP)**. Using OpenTelemetry, you can now:

  * **Propagate context** across MCP client-server boundaries
  * Generate **end-to-end traces** of your AI system across services and languages
  * Gain full visibility into how models access and use external context

  The `openinference-instrumentation-mcp` package handles this for you by:

  * Creating spans for MCP client operations
  * Injecting trace context into MCP requests
  * Extracting and continuing the trace context on the server
  * Associating the context with OTEL spans on the server side

  ### **Set up**

  1. Instrument both MCP client and server with OpenTelemetry.
  2. Add the `openinference-instrumentation-mcp` package.
  3. Spans will propagate across services, appearing as a **single connected trace** in Phoenix.

  <Card title="phoenix/tutorials/mcp/tracing_between_mcp_client_and_server at main · Arize-ai/phoenix" icon="github" href="https://github.com/Arize-ai/phoenix/tree/main/tutorials/mcp/tracing_between_mcp_client_and_server" horizontal>
    GitHub
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  ### **Walkthrough Video**

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  ### **Acknowledgments**

  Big thanks to Adrian Cole and Anuraag Agrawal for their contributions to this feature.
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