MLflow Tracing Instrumentation Guide
Language-Specific Guides
Based on the user's project, load the appropriate guide:
- •Python projects: Read
references/python.md - •TypeScript/JavaScript projects: Read
references/typescript.md
If unclear, check for package.json (TypeScript) or requirements.txt/pyproject.toml (Python) in the project.
What to Trace
Trace these operations (high debugging/observability value):
| Operation Type | Examples | Why Trace |
|---|---|---|
| Root operations | Main entry points, top-level pipelines, workflow steps | End-to-end latency, input/output logging |
| LLM calls | Chat completions, embeddings | Token usage, latency, prompt/response inspection |
| Retrieval | Vector DB queries, document fetches, search | Relevance debugging, retrieval quality |
| Tool/function calls | API calls, database queries, web search | External dependency monitoring, error tracking |
| Agent decisions | Routing, planning, tool selection | Understand agent reasoning and choices |
| External services | HTTP APIs, file I/O, message queues | Dependency failures, timeout tracking |
Skip tracing these (too granular, adds noise):
- •Simple data transformations (dict/list manipulation)
- •String formatting, parsing, validation
- •Configuration loading, environment setup
- •Logging or metric emission
- •Pure utility functions (math, sorting, filtering)
Rule of thumb: Trace operations that are important for debugging and identifying issues in your application.
Feedback Collection
Log user feedback on traces for evaluation, debugging, and fine-tuning. Essential for identifying quality issues in production.
See references/feedback-collection.md for:
- •Recording user ratings and comments with
mlflow.log_feedback() - •Capturing trace IDs to return to clients
- •LLM-as-judge automated evaluation
Reference Documentation
Production Deployment
See references/production.md for:
- •Environment variable configuration
- •Async logging for low-latency applications
- •Sampling configuration (MLFLOW_TRACE_SAMPLING_RATIO)
- •Lightweight SDK (
mlflow-tracing) - •Docker/Kubernetes deployment
Advanced Patterns
See references/advanced-patterns.md for:
- •Async function tracing
- •Multi-threading with context propagation
- •PII redaction with span processors
Distributed Tracing
See references/distributed-tracing.md for:
- •Propagating trace context across services
- •Client/server header APIs