Phoenix Evals

Build evaluators for AI/LLM applications. Code first, LLM for nuance, validate against humans.

Quick Reference

Task	Files
Setup	setup-python, setup-typescript
Decide what to evaluate	evaluators-overview
Choose a judge model	fundamentals-model-selection
Use pre-built evaluators	evaluators-pre-built
Build code evaluator	evaluators-code-{python|typescript}
Build LLM evaluator	evaluators-llm-{python|typescript}, evaluators-custom-templates
Batch evaluate DataFrame	evaluate-dataframe-python
Run experiment	experiments-running-{python|typescript}
Create dataset	experiments-datasets-{python|typescript}
Generate synthetic data	experiments-synthetic-{python|typescript}
Validate evaluator accuracy	validation, validation-evaluators-{python|typescript}
Sample traces for review	observe-sampling-{python|typescript}
Analyze errors	error-analysis, error-analysis-multi-turn, axial-coding
RAG evals	evaluators-rag
Avoid common mistakes	common-mistakes-python, fundamentals-anti-patterns
Production	production-overview, production-guardrails, production-continuous

Workflows

Starting Fresh: observe-tracing-setup → error-analysis → axial-coding → evaluators-overview

Building Evaluator: fundamentals → common-mistakes-python → evaluators-{code\|llm}-{python\|typescript} → validation-evaluators-{python\|typescript}

RAG Systems: evaluators-rag → evaluators-code-* (retrieval) → evaluators-llm-* (faithfulness)

Production: production-overview → production-guardrails → production-continuous

Rule Categories

Prefix	Description
fundamentals-*	Types, scores, anti-patterns
observe-*	Tracing, sampling
error-analysis-*	Finding failures
axial-coding-*	Categorizing failures
evaluators-*	Code, LLM, RAG evaluators
experiments-*	Datasets, running experiments
validation-*	Validating evaluator accuracy against human labels
production-*	CI/CD, monitoring

Key Principles

Principle	Action
Error analysis first	Can't automate what you haven't observed
Custom > generic	Build from your failures
Code first	Deterministic before LLM
Validate judges	>80% TPR/TNR
Binary > Likert	Pass/fail, not 1-5