It never sees your sentence. It sees a list of chunks — and the chunks are not the words you would have picked.
Real output from o200k, the tokenizer behind today’s GPT models — these chunks are what it calls tokens. Grey dots mark a leading space — it belongs to the token.
The problem it explains
The same word is chopped differently depending on the space in front of it. Ask about letters and the model is guessing about pieces it never sees apart.
How it works
See it in action
Nobody labelled these groups — they fall out of which words keep showing up in the same company. Tap a word to see its nearest neighbours.
The payoff
Because meaning became geometry, “find me something similar” turns into “find the nearest points”.
That single move is what makes search, recommendations and — later in this series — a model looking things up before it answers all possible.
So what
Before any thinking happens, your sentence has already become chunks, then numbers, then coordinates.