Definition
The degradation in an agent's ability to find, follow, or correctly weigh relevant information as its accumulated context becomes longer, noisier, stale, repetitive, or internally conflicting. Context rot can appear before the formal context-window limit because the problem is attention and instruction use, not merely storage capacity.
Distinguish it from nearby terms
Context-window overflow means the input no longer fits. Context rot means the input fits but performs poorly. Context poisoning introduces malicious or misleading material; ordinary context rot can emerge from benign history, duplicated attempts, obsolete plans, and unresolved contradictions.
Check your understanding
A longer context window can postpone truncation without preventing important instructions from being buried under irrelevant history.