diff --git a/TODO.org b/TODO.org
index 0f2fe683..d8ca6c01 100644
--- a/TODO.org
+++ b/TODO.org
@@ -16,7 +16,9 @@ Decided 2026-09-25: the typed read-only text is =str= (renamed from =string=); =
 is new, owned, growable, always valid UTF-8, through an allocator. The prelude's text
 builders return =String=; =(Vec u8)= stays for raw bytes. Text is UTF-8 everywhere and
 a character is a code point; dyn gets a character tag, so \\I prints as \\I.
-Waits on the dyn-unless-annotated design.
+Dyn text stays immutable, with chars and text converting to and from a dyn
+vector of characters; length and indexing count characters on dyn text and bytes on
+str. Waits on the dyn-unless-annotated design.
 
 ** NEXT Any typed container crosses into dyn as a view
 Decided 2026-09-25: every element type (all numbers, chars, structs, nested arrays)