diff --git a/TODO.org b/TODO.org
index 4ffc4ba8..82913188 100644
--- a/TODO.org
+++ b/TODO.org
@@ -864,7 +864,8 @@ correct code, so any per-push flag is a false positive by the language's own
 semantics; the refined version needs liveness across control flow, which is the
 flow tracking that was repealed.
 
-** TODO Catching a use-after-release statically
+** NEXT Catching a use-after-release statically
+Decided 2026-09-25: a study, not a build — how arena memory escapes in real Flan code, and whether a sound lexical check would catch most of it. The result goes in docs/BUILT.md; nothing is built on it without the author.
 Open, and for the first time with evidence available: the epoch trap is built, and
 there is a =Vec= to write real arena programs with, so whether the escapes that
 actually occur are lexical can now be answered. The next thing to look at, not the