#Engenharia De Contexto

Half the prompt techniques disappeared because the model learned them on its own. The other half became API parameters. What survived, what turned into folklore, and why in a real system the problem stopped being the sentence and became what goes into the context window.

You send a one-line question and /usage reports a whole day's worth of consumption. Saving tokens in a coding assistant has nothing to do with prompt size: it's about prefix caching. How it works in Claude Code, Codex, and Cursor, the seven actions that invalidate it without you noticing, how to measure it with cache_read vs cache_creation, and eight levers to stretch the session.