Table of Contents Manual Tracing, Scores, and Evaluation with Langfuse (Self-Hosted) Why Manual Tracing Matters for LLM Observability Decorator vs Manual Tracing: When to Use Which Manual Tracing with the Langfuse Low-Level API Why Manual Tracing Matters (Even If You Use Decorators) Full Manual Tracing Implementation with Langfuse Code Walkthrough: Langfuse Manual Tracing Pipeline Creating Manual Traces in Langfuse Running the Langfuse Manual Tracing Script Viewing Manual Traces in the Langfuse Dashboard Manual vs Decorator Tracing in Langfuse LLM Evaluation Metrics and Quality Scoring with Langfuse Adding LLM Evaluation Metrics Beyond Manual Tracing Code Walkthrough: evaluation_metrics.py Running the LLM Evaluation Metrics Pipeline Conceptual Mockup: Evaluation Trace in Langfuse Real Trace from Our Self-Hosted Langfuse Dashboard Why LLM Evaluation Metrics Matter vLLM Diagnostics and Health Checks for LLM Observability What the vLLM Health Check Script Validates Code Walkthrough: health_check.py Why vLLM…