diff --git a/mps/code/arg.c b/mps/code/arg.c
index edb25ebd8c0..4d2447e5c00 100644
--- a/mps/code/arg.c
+++ b/mps/code/arg.c
@@ -42,12 +42,12 @@ Bool ArgCheckChain(Arg arg) {
 }
 
 Bool ArgCheckSize(Arg arg) {
-  UNUSED(arg);
+  UNUSED(arg); /* TODO: Add and call SizeCheck */
   return TRUE;
 }
 
 Bool ArgCheckAddr(Arg arg) {
-  UNUSED(arg);
+  UNUSED(arg); /* TODO: Add and call AddrCheck */
   return TRUE;
 }
 
@@ -72,7 +72,7 @@ Bool ArgCheckBool(Arg arg) {
 }
 
 Bool ArgCheckCount(Arg arg) {
-  UNUSED(arg);
+  UNUSED(arg); /* TODO: Add and call CountCheck */
   return TRUE;
 }
 
@@ -116,6 +116,8 @@ Bool ArgListCheck(ArgList args)
 }
 
 
+/* ArgPick -- try to pick an argument out of the argument list by keyword */
+
 Bool ArgPick(ArgStruct *argOut, ArgList args, Key key) {
   Index i;
   
@@ -136,14 +138,13 @@ found:
       break;
     ++i;
   }
-
   return TRUE;
 }
 
 
 /* C. COPYRIGHT AND LICENSE
  *
- * Copyright (C) 2001-2002 Ravenbrook Limited <http://www.ravenbrook.com/>.
+ * Copyright (C) 2001-2013 Ravenbrook Limited <http://www.ravenbrook.com/>.
  * All rights reserved.  This is an open source license.  Contact
  * Ravenbrook for commercial licensing options.
  * 
diff --git a/mps/code/arg.h b/mps/code/arg.h
index 2a1385a8dfb..f50107b593f 100644
--- a/mps/code/arg.h
+++ b/mps/code/arg.h
@@ -11,9 +11,14 @@
 
 #include "mpmtypes.h"
 
-/* KeyStruct -- keyword argument structure */
 
-/* FIXME: Whether to have a check field should be conditional on variety */
+/* KeyStruct -- keyword argument structure
+ *
+ * NOTE: Whether or not to have an argument checking field and functions
+ * could be conditional on build variety.  Checking arguments isn't on
+ * the critical path, but this might save space if the MPS is being
+ * deployed in a tight memory situation.
+ */
 
 #define KeySig          ((Sig)0x519CE111) /* SIGnature KEYyy */
 typedef struct mps_key_s {
@@ -49,7 +54,7 @@ extern Bool ArgCheckCount(Arg arg);
 
 /* C. COPYRIGHT AND LICENSE
  *
- * Copyright (C) 2001-2002 Ravenbrook Limited <http://www.ravenbrook.com/>.
+ * Copyright (C) 2001-2013 Ravenbrook Limited <http://www.ravenbrook.com/>.
  * All rights reserved.  This is an open source license.  Contact
  * Ravenbrook for commercial licensing options.
  *