Context rot
Also known as: lost in the middle · context degradation
Context rot is the observed drop in a model’s effective use of its context as it grows longer. Information in the middle of a long prompt gets used less reliably than material at the start or end.
It’s the “lost in the middle” phenomenon.
- Short context: model uses it all well.
- Very long context: model attends to the edges, drops the middle.
Design around it: put the most important instructions and facts at the *start* and *end* of the prompt, not buried in the middle. And consider RAG over one giant prompt.