---
title: "Context engineering"
description: "Prompt engineering grew up: context engineering is deciding what the model sees each turn — system instructions, retrieved chunks, tool results, memory, hi"
canonical_url: "https://fanout.sh/ai-engineering/lessons/context-engineering"
md_url: "https://fanout.sh/ai-engineering/lessons/context-engineering.md"
access: "public"
---

# Context engineering

Prompt engineering grew up: context engineering is deciding what the model sees each turn — system instructions, retrieved chunks, tool results, memory, hi

## Public overview

Prompt engineering grew up: context engineering is deciding what the model sees each turn — system instructions, retrieved chunks, tool results, memory, history — under a hard token budget. Treat the context window as a curated working set, not a dumping ground; most agent failures are context failures.

---
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