A Compacted Session Drops a Constraint the User Stated Once

A long agentic session (60+ tool calls) hits your context-window threshold and triggers compaction. Ten steps after compaction, the agent violates a constraint the user stated early in the conversation — "never modify files under /generated, they're rebuilt by CI" — because that instruction, along with the turns around it, was summarized away.

1. Diagnose what actually went wrong — is this a compaction bug, or a memory-architecture problem?
2. Propose a fix at the compaction-design level: what should the summarizer preserve, and how do you make that reliable rather than hopeful?
3. Propose a second, independent fix that doesn't depend on compaction behaving well at all. Why is having both better than either alone?