Context engineer
The one who decides everything that enters the window
A context engineer decides what the model has in front of it at the moment it answers: the documents, the history, the tools on hand, like a clerk assembling the file handed to a judge before the hearing.
- Floor 2The Harness
- P2Writes the application
- Emerging titleIt appeared recently. What it covers is not yet stable from one employer to the next.
What they answer for
The deliverableThe chain that assembles a window: what gets retrieved, what gets cut, what carries over from one conversation to the next. If they leave, answers degrade without anything breaking.
The profile
Five activities, scored 0 to 3- ResearchProducing knowledge that does not yet exist.
- BuildShipping a system that runs, deploys and breaks.
- OperateKeeping it in production: cost, incidents, drift, on-call.
- VerifyMeasuring, testing, attacking. Producing a verdict that holds.
- LeadDeciding, persuading, driving adoption, answering to others.
What the work is
The finding
The role comes from a finding that keeps repeating: for a given model, what changes the quality of an answer is almost always what it was given to read, not how it was asked. The window is a scarce resource, and somebody has to decide what goes in it.
What the role decides
The decisions look less like writing than like design. What do we retrieve, and from where? What do we cut when it will not all fit? What do we keep from one conversation to the next, and in what form? Each of those questions has consequences for cost, latency and accuracy, and none of them has a universal answer.
The trap
The trap is how new the title is. It appeared in adverts less than two years ago, and what it covers still varies a great deal from one employer to the next: architecture work here, document retrieval there. Look at what is asked about memory and about cutting; those are the two places where the serious roles show themselves.
A week in the role
- Chunking and indexing choices, which decide what you will be able to find later.
- Measurements: the same question put through three different window compositions, and the gap recorded.
- Retrieval and assembly code, between the store and the call to the model.
- Cost trade-offs: what you give up putting in the window because it would be paid for on every call.
Ways in
- From application engineering, particularly if you have already run a document retrieval chain.
- From information retrieval or technical documentation, where the work on chunking is the same trade under another name.
- What the role does not require, whatever the advert says: training a model. Nothing is learned; everything is re-read on every call.
Reading an advert
2 signs- The advert talks exclusively about "prompting techniques".
- The title changed, the role did not. Context is what enters the window, not how a sentence is phrased.
- Nothing is said about memory, or about what happens when the content will not fit in the window.
- Those are the two hard questions of the trade. An advert that does not pose them is describing an integration, not this role.