Evaluate in two layers: did retrieval find the source passage, and is the answer grounded in it and correct. Looking only at answers can fool you: one study found that when the context wasn't enough to answer, models still got 35% to 62% right using their own knowledge, which breaks on questions only your organization can answer. Use order 11's test questions for both layers, and evaluate permission-crossing and unanswerable questions too; calibrate LLM judges against human samples. After launch, turn escalated and complained-about conversations into failure cases, hand them back to document owners, and add them to the test set.
Lecture 13 is about limiting what agents can access and do. The slides open with five real incidents, sort them into four threat models (malicious user, prompt injection, agent error, improper means), then give four layers of defense: red teaming and safety training, sandboxes and credential brokering, monitoring, and safety evaluation. The easiest point to miss: hiding the API key does not stop an agent from misusing the access behind it.
Stage 6 is both the endgame and the starting point of the AI-Native SDLC: a monitoring script detects an anomaly → Claude writes a diagnosis as intent.md → it flows through the entire development pipeline. Humans shift from 'starting work' to 'triaging and reviewing work.'
Workers Observability is for debugging and request tracing; Workers Analytics Engine is for high-cardinality product events and custom metrics; GraphQL Analytics API is for querying existing Cloudflare product data. Keeping those roles separate prevents logs from becoming a database and keeps billing, monitoring, and product analytics from blending together.
MLOps interviews test whether you have experience pushing models to production. Key topics: ML pipeline CI/CD (how it differs from software CI/CD), model registry and version management, A/B testing design and pitfalls, inference scaling strategies (horizontal scaling, model compression, caching), and production monitoring and alerting design.
Langfuse is currently the most mature open-source LLM Observability platform. This post covers four core capabilities — Tracing, Prompt Management, Evaluation, and Datasets — showing you how to use them in real projects.
Rolling your own traces is good enough, but open-source tools save you a lot of work. Langfuse, Phoenix, and LangSmith each have their niche — the right choice depends on your trade-offs around self-hosting, open source, and integration complexity.
The hardest part of a RAG system isn't building it — it's figuring out why a particular answer went wrong. Pipeline Tracing records every step's decisions and data so debugging has a clear trail to follow.