Steward is not another word for brain
Once a memory tool gains search and model calls, it is easy to call it an assistant. Then it answers questions, selects what matters, and eventually deletes what looks old. Three convenient steps have turned the steward into the author of memory.
Vestige draws the boundary in the other direction. Judgment occurs in a live brain session where a responsible reader sees current truth, cost, and history. After a decision, the tool applies it through one mediated path and records it. This fixes the place where intelligence must accept responsibility.
Observation is not a verdict
A high token count, an old date, and a similar sentence are all signals. None is a deletion verdict. A short sanctuary principle may never be merged, while a long failure record may be the cheapest device preventing the next incident.
The interface can expose Weight, Drift, and Related without offering Clean Automatically. Signals order the questions a person should ask; answers come from reading the source in context. When a measurement gains authority, the proxy consumes the purpose.
The boundary appears under failure
If a brain provider is unavailable, the steward should continue serving source and history while delegation fails explicitly. If the search index breaks, live truth and the ledger remain intact and the index can be rebuilt. If current authority cannot be evaluated, writes close safely instead of trusting stale permission.
That failure shape proves the product definition. With brain, index, and cache absent, truth and history must survive and unauthorized mutation remain impossible. Then Vestige stays a bounded steward rather than a god-object calling itself a memory platform.
Helping memory and authoring memory are different powers.
A tool should expose evidence, cost, and paths while judgment remains in the live session that can own it.