Deep dives

Context rot

Context rot is the quality degradation that hits AI agents as long, unfiltered context accumulates - and why externalizing memory beats stretching the window.

Context rot is the performance degradation that happens when AI agents process increasingly long, unfiltered context - and it's why long agentic sessions contradict their own earlier decisions.

The mechanism

Models don't attend uniformly across a long window. As a session accumulates tool output, dead ends, and stale plans, the signal the model needs competes with noise it can't discard. Quality drops before the window is technically full - more tokens, worse answers.

The fix is selection, not size

The robust pattern is to keep the working context short and externalize durable knowledge: write decisions and facts out as they happen, then re-inject only the relevant slice when needed. That is exactly the Unison loop - ingest as you go, recall at task boundaries, with weakEvidence abstention instead of padding.

A bigger window doesn't fix rot; it postpones it while raising cost. See Why a bigger context window doesn't solve agent memory.

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