diff --git a/TODO.org b/TODO.org
index 0b8fcdc2..9d9e232d 100644
--- a/TODO.org
+++ b/TODO.org
@@ -1379,6 +1379,10 @@ CLOSED: [2026-09-25]
 dev build wipes it at a top-level agent poll; an expression run at a stop gets a scratch temp arena.
 
 * Runtime
+** NEXT A dyn vector is a value
+Decided (141): binding, assigning, capturing or passing a dyn vector acts like a typed fixed
+array's copy; the pointer is shared until either side writes, which copies first. Rules out
+dyn vectors as shared references, where annotating a binding would change what prints.
 
 ** TODO Heap quarantine in dev
 A dev build could hold freed heap blocks back from reuse for a while (Zig's debug allocator), so a read after a free sees poison rather than a new owner's data.