The prompt is the page

The prompt is everything handed to the model before it writes. Nothing off the page exists.

Part of the What is this thing? track on lAItest.

The model is handed a page with your text at the top and asked to keep writing.

Everything that shapes the answer has to already be on that page.

Prompt means input, not question

A prompt is the whole block of text given to the model for one run: your question, plus any instructions, plus any file you attached, plus every earlier turn of the conversation. It is not just the sentence you typed. If a fact is not on the page, the model cannot use it — except through whatever it absorbed in training, which is a far less reliable place to keep facts.

A common misconception

Commonly believed: Getting good answers is about phrasing: being polite, or knowing the magic words.

Actually: It is about what is on the page. "Fix my code" with no code attached gives the model nothing to work from, and it will invent a plausible bug. Paste the code, say what it should do, say what it does instead, and there is now an actual problem in front of it. Most disappointing answers are missing context, not missing magic.

What comes back is text too

The reply is called the completion, or the output tokens. Input and output are counted separately and priced separately, and output almost always costs more per token. That is not a markup: the model has to run once for every single piece it produces, while the whole input is read in one pass.

In one sentence

The prompt is the page. Anything not on the page does not exist to the model.