diff --git a/TODO.org b/TODO.org
index af52b515..cc934a8c 100644
--- a/TODO.org
+++ b/TODO.org
@@ -726,6 +726,11 @@ of !=.
 
 * Checker
 
+** NEXT A dyn value takes .field and [:key]
+Decided 2026-09-26: on a dyn value, ~x.name~ / ~(.name x)~ reads ~(get x :name)~ and
+assigning it is ~(put x :name v)~ — a class slot or a map key; ~m[:k]~ indexes a dyn
+map as ~(get m :k)~, and assigning it puts.
+
 ** DONE A slice from a C pointer, and a pointer cast
 CLOSED: [2026-09-25]
 =(slice-from p n)= and =((Ptr U) p)=, both unchecked. Rules out pointer arithmetic