Glossary: RAG, MCP, LLM, HRV

A quick glossary for the terms that came up in the poll above.

RAG — Retrieval-Augmented Generation. An architecture that extends an LLM with an external knowledge base instead of relying solely on what the model “remembers” (its weights). In other words: a vector database plugged into your AI.

MCP — Model Context Protocol. A way to give an AI access to external services and let it control them — essentially a set of API methods wrapped in a format the LLM can actually understand and use.

LLM — Large Language Model. A neural network trained on massive amounts of text to predict the next token. It can generate, analyze, and transform text. Examples: GPT-5, Claude, LLaMA, Gemini.

HRV — Heart Rate Variability. A measurement of the time intervals between heartbeats. High HRV → good recovery, low stress, ready to perform. Low HRV → under-recovered, stressed, sick, or overtrained.