Compression Monitor

Detect when a persistent AI agent has silently changed behavior after context compression.

The Problem

Agents compress their history when context fills up. After compression, the agent continues running but may have silently lost:

• Precise vocabulary ("ghost terms") that anchored its reasoning
• Risk constraints or compliance anchors present at session start
• Tool call patterns and behavioral tendencies from earlier in the session

The agent reports no change. Benchmarks don't catch it. The behavior is different.

Three Measurement Signals