diff --git a/TODO.org b/TODO.org
index ccaa82c0..73efe62b 100644
--- a/TODO.org
+++ b/TODO.org
@@ -1730,7 +1730,8 @@ nothing orders the two. The read raised on a closed socket and the test binary
 exited 1 with no failure line, which is the worst shape a failure can have when
 a lane is judged on the exit status.
 
-** TODO A program driven by a real flan dev daemon under a sanitizer
+** NEXT A program driven by a real flan dev daemon under a sanitizer
+Decided 2026-09-25: =flan dev --sanitize= builds the host under ASan/UBSan on the LLVM backend (refused by name with =--x86=), and the @sanitize alias gains a case driving a real session through reloads and a break.
 The daemon builds its host through its own path and the CLI has no way to pass a
 sanitizer flag to it. Named as the check worth adding next; a day rather than an
 hour. The x86 backend is not a gap here — that pair is refused by name, because