Combining Phoenix with Haystack enables effortless tracing, enhanced debugging, and comprehensive evaluations for LLM applications and search systems. With just a single line of code, Phoenix provides deep insights into application behavior through tracing, allowing developers to pinpoint issues quickly. To set up a basic RAG application using Haystack and Phoenix, install the necessary libraries, launch a local Phoenix instance, connect it to your application, and add the Haystack auto-instrumentor to generate telemetry. Initialize your Haystack environment by setting up a document store, retriever, and reader, and build a RAG pipeline with components such as a retriever, prompt builder, and LLM. Finally, call the Haystack pipeline with a question and view the resulting LLM traces in Phoenix for further analysis.