Context window

The amount of text a model can hold in mind at once, counting both what you give it and what it writes back. It is measured in tokens. Once a conversation or document runs past the limit, the model starts losing track of the earliest parts. This explains a common frustration, that a tool seems to forget something said earlier, and it has practical consequences in healthcare: a long record or a lengthy guideline may not fit in one window, so what the model can reason over at any moment is bounded. Larger context windows cost more to run, which is part of why capability and price move together.

Terms like this come up in real clinical scenarios across the HelloAI courses: bite-sized modules with verifiable certificates. An account takes one minute, no password needed.