Glossary · Phase 10 · Agent harnesses
Context rot
The drop in a model's accuracy as its context fills with old or irrelevant material.
Bigger isn't free even when it fits. On a buried desk, the note you need is still there, and you won't find it. Models attend less sharply to details buried in a huge context, sometimes called context rot. So the goal isn't only to fit, but to keep the context full of what matters now.
Try it now
The cut starts on a user message of tool results, so it steps back once, to the assistant message that made those calls.
Learn it properly
Managing the context window · Budgets, clearing old tool results, compaction and a cacheable prefix. About 40 minutes.
Other terms from the same lesson
- compaction: Replacing the older part of a conversation with a summary, keeping recent turns, so a long task fits in the context window.
- context editing: Removing or shrinking parts of a conversation, such as old tool results, to save space. The Claude API can do it on the server.
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