diff --git a/mps/code/format.c b/mps/code/format.c
index 9867f562167..4aef38928fd 100644
--- a/mps/code/format.c
+++ b/mps/code/format.c
@@ -26,7 +26,10 @@ Bool FormatCheck(Format format)
          || format->variety == FormatVarietyAutoHeader);
   CHECKL(RingCheck(&format->arenaRing));
   CHECKL(AlignCheck(format->alignment));
-  /* @@@@ alignment should be less than maximum allowed */
+  /* TODO: Define the concept of the maximum alignment it is possible to
+     request from the MPS, document and provide an interface to it, and then
+     check that this alignment is not greater than that, as well as all other
+     alignments. */
   CHECKL(FUNCHECK(format->scan));
   CHECKL(format->variety == FormatVarietyFixed
          ? format->skip == NULL : FUNCHECK(format->skip));
diff --git a/mps/code/mpmss.c b/mps/code/mpmss.c
index 5c98b1da9ac..e98961986cf 100644
--- a/mps/code/mpmss.c
+++ b/mps/code/mpmss.c
@@ -15,7 +15,9 @@
 #include <stdarg.h>
 
 
-/* @@@@ Hack due to missing mpscmfs.h */
+/* TODO: Decide whether we should support the MPS pool class externally,
+   create mpscmfs.h, and replace this extern with proper use of its
+   interface. */
 extern mps_class_t PoolClassMFS(void);