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# 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.

### **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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