Explore a comprehensive tutorial on evaluating the performance of language models like OpenAI's GPT-3 using Langchain and custom prompts. Learn to create environments, install necessary packages, and review code for LLM question-answering tasks. Discover how to craft custom prompts for LLM evaluation and analyze code for agent evaluation with tools. Gain insights into using datasets from Huggingface and leverage Langchain's evaluation capabilities. Follow along with a detailed timeline, from introduction and demo to final code review, to enhance your understanding of LLM performance assessment.