Definition
A token represents a fundamental unit of text or data processed by large language models (LLMs). Think of it as a word, part of a word, or punctuation mark that the AI breaks down for analysis. When you interact with an LLM, your input is tokenized, and the model generates output by predicting subsequent tokens. Understanding tokenization is crucial for managing computational costs and optimizing model performance, as different models have varying token limits and pricing structures. For instance, a sentence like 'AI is transformative' might be broken into tokens such as 'AI', 'is', 'transform', and '##ative'. This differs from a character, which is a single letter or symbol, as a token can encompass multiple characters or just a single one. Knowledge of tokens is relevant for AI and machine learning domains on exams like AWS Certified Machine Learning Specialty.