Status: IN
The write path's cheapness is partially enabled by the perimeter defense model: because inputs are normalized once at system boundaries and internal callers are trusted, writes operate on pre-validated data without redundant checking, keeping the asymmetric cost model's write side genuinely lightweight beyond just routing simplicity.
perimeter defense and asymmetric cost allocation are independently motivated but mutually reinforcing — the trust model explains HOW writes stay cheap, not just THAT they are cheap
Depends on (SL): perimeter-defense-ensures-data-quality, writes-are-cheap-reads-pay