Context Rot

What is Context Rot

Context rot is a drop in reasoning quality that shows up as a session's context window fills with long, noisy, or repetitive history, distinct from simply running out of room. A session can still have plenty of token budget left and still reason noticeably worse than it did earlier, because the signal it needs is now buried in a much larger pile of history to search through.

It tends to show up first as small things: re-reading a file it already read, repeating a question it already answered, losing track of a constraint stated many turns earlier. None of these individually looks like a hard failure, which is part of what makes context rot easy to miss until the pattern has already cost real time.

The fix is rarely just waiting it out. Compaction can help by summarizing older noise away, but a session that has accumulated enough failed attempts and dead ends often does better starting fresh with a clean, deliberately scoped context than continuing to build on top of an increasingly cluttered one. Tighter task scoping up front is the more reliable prevention.