LEVEL 01 · LESSON 02
Context windows
What the model can use now depends on the context the application actually sends.
What it is
The context window is the model’s capacity for information within one request. Instructions, conversation history, retrieved documents, tool results, and output all compete for a finite budget, subject to the model’s limits.
Why it matters
A long conversation does not guarantee that every earlier detail remains available. An application may trim, summarize, or retrieve history before sending the next request.
A business example
A procurement assistant compares supplier proposals. If a key exclusion appears in a document that was omitted to fit the request, the assistant may recommend the wrong supplier even though the user uploaded that document earlier.
How it actually works
The application assembles a request within the model’s input and output limits. If there is too much material, it must reduce it or split the task. Retrieval selects relevant evidence; summarization compresses it but may lose detail. Even when everything fits, models may miss important passages. Test with realistic document lengths and place essential instructions clearly rather than assuming a larger window solves the problem.
A common misconception
The context window is not permanent memory or a guarantee of perfect attention to every included sentence.
ONE SENTENCE TO REMEMBER
What the model can use now depends on the context the application actually sends.
CHECK YOUR UNDERSTANDING
Late in a long chat, an assistant ignores a constraint you gave in your first message. Which explanation is most likely?
Show the answer
Answer: C.
A model can only use what the application actually sends in the current request. Long histories are often trimmed or summarized, and even included text can be missed. Restating essential instructions clearly is more reliable than assuming a long chat keeps everything in view.
Take it into your next meeting
How would you check that the decisive clause reached the model?
One more concept, understood.
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