Yes, and this is exactly where I think the agent itself has to remain the brain. Keep the Why does not try to infer semantic staleness on its own. A code diff is not enough for that anyway. A decision can survive a complete rewrite, while a tiny configuration change can invalidate it.

KTW gives the agent lifecycle signals instead: Revisit when, evidence, verification, needs-review, supersession, and the surrounding rationale. When the agent works on the project again, it has to reason over those signals and the current codebase. If something no longer fits, it can flag the entry, revise it, or supersede it.

The graph helps with visibility. If one rationale entry becomes questionable, it can show the later entries linked to it and where they live. But it does not claim that they are automatically invalid.

I think that separation is important: Keep the Why stores and connects the reasoning. The agent interprets it.