llm-evals-engineer

Instrument, evaluate, and production-harden LLM applications with tracing, metrics, and guardrails.

Updated Jul 16, 2026
One-click install
npx skills add https://github.com/Cloud-Byte-Consulting/plugins --skill llm-evals-engineer-cloud-byte-consulting
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: llm-evals-engineer
Source: https://github.com/Cloud-Byte-Consulting/plugins/tree/main/ai-engineering/skills/llm-evals-engineer
Command: npx skills add https://github.com/Cloud-Byte-Consulting/plugins --skill llm-evals-engineer-cloud-byte-consulting

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? LLM applications often ship on vibes — they seem to work, but nobody can say whether retrieval or generation is failing, whether a prompt change regressed quality, or whether spend is under control. This Skill takes an LLM app from unmeasured to gated: tracing every query, scoring quality with RAG metrics and LLM judges, gating deploys on eval thresholds, and enforcing production controls like prompt versioning, budgets, and input guardrails. ## Core Features & Use Cases - Tracing architecture: Dual instrumentation (callback handler plus decorator) producing trace-per-query spans grouped by session, with tokens, cost, and latency visible per named span. - Metric suite with retriever/generation split: Ragas-style metrics (context precision/recall, entities recall, noise sensitivity, faithfulness, response relevancy, tool call accuracy) that isolate whether failures come from retrieval or generation. - LLM-as-judge pipelines and CI gating: Judge evaluators wired to trace fields, hand-verified against labeled samples, then run in CI to block deploys when metrics drop below thresholds. - Production hardening: Prompt registry with version-linked traces, TTL-bounded chat history with token trimming, NeMo-style input rails, and gateway controls (virtual keys, budgets with durations, rpm/tpm limits) via LiteLLM. - Use Case: Your RAG chatbot is hallucinating in production. Use this Skill to add tracing, build a 50–200 example eval set from real traces, measure faithfulness versus context recall to pinpoint whether retrieval or generation is at fault, and gate future prompt changes on the metric suite. ## Quick Start Ask the agent to add tracing and a faithfulness-plus-context-recall eval suite to your RAG chatbot using Langfuse and Ragas, then gate deploys on the results.

Frequently Asked Questions about llm-evals-engineer

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I evaluate whether my RAG app is hallucinating?

Measure faithfulness, which checks that every claim in the answer is supported by the retrieved context. Pair it with context recall: low faithfulness with high recall indicates a generation problem, while low faithfulness with low recall means retrieval never fetched the facts.

How do I add tracing to a LangChain LLM application?

Create one Langfuse callback handler before the conversation loop and pass it on every invoke via config, then add @observe decorators to non-framework functions like data loaders. Use trace-per-query spans with session and user propagation so each query shows tokens, cost, and latency.

What metrics should I use for RAG retrieval quality?

Use context precision to catch noisy retrieval, context recall to catch missing chunks or bad k, context entities recall for fact-heavy domains, and noise sensitivity to detect when irrelevant context derails the generator. These isolate retrieval failures from generation failures.

Why does my LLM-as-judge produce plausible but wrong scores?

Mis-mapped variables are the usual cause — for example, judging faithfulness against the query instead of the retrieved context fails silently. After wiring any evaluator, hand-check 3–5 judged traces and confirm the judge's reasoning references the correct text.

Can I use tools other than Langfuse and Ragas with this approach?

Yes, the stack is defined as capability slots — tracing platform, metric suite, rails engine, gateway, and history store — with Langfuse, Ragas, NeMo Guardrails, LiteLLM, and Redis as reference fills. The architecture and workflow stay the same when you substitute vendors.

When should I use agent-trust-auditor instead of LLM app evals?

Use agent-trust-auditor when judging autonomous agent behavior — multi-step plans, tool-use trajectories, and delegation gates. This Skill evaluates the application layer: retrieval and generation quality of RAG and chatbot responses.