Context engineering
Deciding what a model gets to see, and what it must not — the discipline that replaced prompt engineering once agents got long-running.
Also called context window management
Prompt engineering focused on phrasing. Context engineering decides what the model gets: files, history, prior decisions, tools, ordering, and cost. It also decides what to leave out.
I did not expect subtraction to matter so much. Giving a model everything works worse than giving it the right things, especially during a long session. Retrieval is easy. The harder decision is what does not belong.
It is also the part that transfers from my old job. Writing a spec for five engineers eight time zones away is the same problem: you cannot answer follow-up questions in real time, so everything that matters has to be in the document, and everything that does not has to be out of it.
See also Harness and Distributed teams.
Linked from
- Toward a spec that survives twelve time zones post
- Distributed teams topic
- Harness topic