diff --git a/include/mcastu.h b/include/mcastu.h
new file mode 100644
index 000000000..fd59871c9
--- /dev/null
+++ b/include/mcastu.h
@@ -0,0 +1,35 @@
+
+
+#define MCF_NONE     0x0000
+#define MCF_INDIRECT 0x0001 /* untargeted/indirect spell */
+#define MCF_SIGHT    0x0002 /* monster needs to see hero */
+#define MCF_HOSTILE  0x0004 /* cast by hostile monsters only */
+
+#if defined(MCASTU_ENUM)
+#define MONSPELL(def, flags) MCAST_##def
+#elif defined(MCASTU_INIT)
+#define MONSPELL(def, flags) flags
+#endif
+
+MONSPELL(PSI_BOLT, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(OPEN_WOUNDS, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(LIGHTNING, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(FIRE_PILLAR, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(GEYSER, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(DEATH_TOUCH, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(CURE_SELF, MCF_INDIRECT),
+MONSPELL(HASTE_SELF, MCF_INDIRECT),
+MONSPELL(DISAPPEAR, MCF_INDIRECT),
+MONSPELL(AGGRAVATION, MCF_INDIRECT|MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(STUN_YOU, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(WEAKEN_YOU, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(CONFUSE_YOU, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(PARALYZE, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(BLIND_YOU, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(DESTRY_ARMR, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(CURSE_ITEMS, MCF_HOSTILE|MCF_SIGHT),
+MONSPELL(INSECTS, MCF_HOSTILE|MCF_INDIRECT|MCF_SIGHT),
+MONSPELL(SUMMON_MONS, MCF_HOSTILE|MCF_INDIRECT|MCF_SIGHT),
+MONSPELL(CLONE_WIZ, MCF_HOSTILE|MCF_INDIRECT|MCF_SIGHT),
+
+#undef MONSPELL
diff --git a/src/mcastu.c b/src/mcastu.c
index 3e32f2e4f..0d8af9d68 100644
--- a/src/mcastu.c
+++ b/src/mcastu.c
@@ -5,32 +5,17 @@
 
 #include "hack.h"
 
+#define MCASTU_ENUM
 enum mcast_spells {
-    MCAST_PSI_BOLT = 0,
-    MCAST_OPEN_WOUNDS,
-    MCAST_LIGHTNING,
-    MCAST_FIRE_PILLAR,
-    MCAST_GEYSER,
-    MCAST_DEATH_TOUCH,
-
-    MCAST_CURE_SELF,
-    MCAST_HASTE_SELF,
-    MCAST_DISAPPEAR,
-
-    MCAST_AGGRAVATION,
-    MCAST_STUN_YOU,
-    MCAST_WEAKEN_YOU,
-    MCAST_CONFUSE_YOU,
-    MCAST_PARALYZE,
-    MCAST_BLIND_YOU,
-
-    MCAST_DESTRY_ARMR,
-    MCAST_CURSE_ITEMS,
-
-    MCAST_INSECTS,
-    MCAST_SUMMON_MONS,
-    MCAST_CLONE_WIZ
+    #include "mcastu.h"
 };
+#undef MCASTU_ENUM
+
+#define MCASTU_INIT
+static int mcast_flags[] = {
+    #include "mcastu.h"
+};
+#undef MCASTU_INIT
 
 staticfn void cursetxt(struct monst *, boolean);
 staticfn int choose_magic_spell(struct monst *);
@@ -965,18 +950,8 @@ mcast_spell(struct monst *mtmp, int dmg, int spellnum)
 staticfn boolean
 is_undirected_spell(int spellnum)
 {
-    switch (spellnum) {
-    case MCAST_CLONE_WIZ:
-    case MCAST_SUMMON_MONS:
-    case MCAST_AGGRAVATION:
-    case MCAST_DISAPPEAR:
-    case MCAST_HASTE_SELF:
-    case MCAST_CURE_SELF:
-    case MCAST_INSECTS:
+    if ((mcast_flags[spellnum] & MCF_INDIRECT) != 0)
         return TRUE;
-    default:
-        break;
-    }
     return FALSE;
 }
 
@@ -990,25 +965,28 @@ spell_would_be_useless(struct monst *mtmp, int spellnum)
      * This check isn't quite right because it always uses your real position.
      * We really want something like "if the monster could see mux, muy".
      */
-    boolean mcouldseeu = couldsee(mtmp->mx, mtmp->my);
+
+    /* spell is only cast by hostile monsters */
+    if ((mcast_flags[spellnum] & MCF_HOSTILE) != 0) {
+        if (mtmp->mpeaceful)
+            return TRUE;
+    }
+
+    /* spell needs the monster to see hero */
+    if ((mcast_flags[spellnum] & MCF_SIGHT) != 0) {
+        boolean mcouldseeu = couldsee(mtmp->mx, mtmp->my);
+
+        if (!mcouldseeu)
+            return TRUE;
+    }
 
     switch (spellnum) {
     case MCAST_CLONE_WIZ:
         /* only the Wizard is allowed to clone himself */
         if (!mtmp->iswiz || svc.context.no_of_wizards > 1)
             return TRUE;
-        if (!mcouldseeu)
-            return TRUE;
-        break;
-    case MCAST_SUMMON_MONS:
-        /* don't summon monsters if it doesn't think you're around */
-        if (!mcouldseeu || mtmp->mpeaceful)
-            return TRUE;
         break;
     case MCAST_AGGRAVATION:
-        /* aggravate monsters, etc. won't be cast by peaceful monsters */
-        if (!mcouldseeu || mtmp->mpeaceful)
-            return TRUE;
         /* aggravation (global wakeup) when everyone is already active */
         /* if nothing needs to be awakened then this spell is useless
            but caster might not realize that [chance to pick it then
@@ -1039,11 +1017,6 @@ spell_would_be_useless(struct monst *mtmp, int spellnum)
         if (mtmp->mhp == mtmp->mhpmax)
             return TRUE;
         break;
-    case MCAST_INSECTS:
-        /* summon insects/sticks to snakes won't be cast by peaceful monsters */
-        if (!mcouldseeu || mtmp->mpeaceful)
-            return TRUE;
-        break;
     case MCAST_BLIND_YOU:
         if (Blinded)
             return TRUE;
diff --git a/sys/msdos/Makefile.GCC b/sys/msdos/Makefile.GCC
index bdf4391e3..17d3a8bd8 100644
--- a/sys/msdos/Makefile.GCC
+++ b/sys/msdos/Makefile.GCC
@@ -416,6 +416,7 @@ GLOBAL_H   = $(PCCONF_H)	$(INCL)/coord.h	   $(INCL)/global.h
 HACK_H	   = $(CONFIG_H)	$(INCL)/context.h  $(DUNGEON_H)	       \
 	     $(DECL_H)	      	$(DISPLAY_H)	   $(INCL)/sym.h       \
 	     $(INCL)/defsym.h   $(INCL)/mkroom.h   $(INCL)/objclass.h  \
+	     $(INCL)/mcastu.h \
 	     $(INCL)/trap.h     $(INCL)/flag.h     $(RM_H)             \
 	     $(INCL)/vision.h   $(INCL)/wintype.h  $(INCL)/engrave.h   \
 	     $(INCL)/rect.h     $(INCL)/hack.h     $(REGION_H)         \
@@ -1407,7 +1408,7 @@ $(TARGETPFX)light.o: light.c $(HACK_H)
 $(TARGETPFX)lock.o: lock.c $(HACK_H)
 $(TARGETPFX)mail.o: mail.c $(HACK_H) ../include/mail.h
 $(TARGETPFX)makemon.o: makemon.c $(HACK_H)
-$(TARGETPFX)mcastu.o: mcastu.c $(HACK_H)
+$(TARGETPFX)mcastu.o: mcastu.c $(HACK_H) ../include/mcastu.h
 $(TARGETPFX)mdlib.o: mdlib.c $(CONFIG_H) ../include/permonst.h \
 		../include/align.h ../include/monattk.h ../include/monflag.h \
 		../include/monsters.h ../include/objclass.h \
diff --git a/sys/unix/Makefile.src b/sys/unix/Makefile.src
index a6fcb6e94..861afc2d3 100644
--- a/sys/unix/Makefile.src
+++ b/sys/unix/Makefile.src
@@ -571,6 +571,7 @@ HACKINCL = align.h artifact.h artilist.h attrib.h botl.h \
 	color.h config.h config1.h context.h coord.h cstd.h decl.h \
 	defsym.h display.h dlb.h dungeon.h engrave.h extern.h flag.h \
 	fnamesiz.h func_tab.h global.h warnings.h hack.h lint.h mextra.h \
+	mcastu.h \
 	micro.h mfndpos.h mkroom.h monattk.h mondata.h monflag.h monst.h \
 	monsters.h nhmd4.h obj.h objects.h objclass.h optlist.h patchlevel.h \
 	pcconf.h permonst.h prop.h rect.h region.h savefile.h selvar.h sym.h \
@@ -896,6 +897,7 @@ $(HACK_H): $(CONFIG_H) ../include/align.h ../include/artilist.h \
 		../include/decl.h ../include/defsym.h ../include/display.h \
 		../include/dungeon.h ../include/engrave.h ../include/flag.h \
 		../include/hack.h ../include/lint.h ../include/mextra.h \
+		../include/mcastu.h \
 		../include/mkroom.h ../include/monattk.h ../include/mondata.h \
 		../include/monflag.h ../include/monst.h ../include/monsters.h \
 		../include/nhlua.h ../include/obj.h ../include/objclass.h \
@@ -1185,7 +1187,7 @@ $(TARGETPFX)light.o: light.c $(HACK_H)
 $(TARGETPFX)lock.o: lock.c $(HACK_H)
 $(TARGETPFX)mail.o: mail.c $(HACK_H) ../include/mail.h
 $(TARGETPFX)makemon.o: makemon.c $(HACK_H)
-$(TARGETPFX)mcastu.o: mcastu.c $(HACK_H)
+$(TARGETPFX)mcastu.o: mcastu.c $(HACK_H) ../include/mcastu.h
 $(TARGETPFX)mdlib.o: mdlib.c $(CONFIG_H) ../include/align.h \
 		../include/artilist.h ../include/attrib.h \
 		../include/context.h ../include/defsym.h ../include/dlb.h \
diff --git a/sys/windows/GNUmakefile b/sys/windows/GNUmakefile
index 6f282c632..d4cbafead 100644
--- a/sys/windows/GNUmakefile
+++ b/sys/windows/GNUmakefile
@@ -794,6 +794,7 @@ HACK_H = $(CONFIG_H) ../include/align.h ../include/artilist.h \
 	../include/decl.h ../include/defsym.h ../include/display.h \
 	../include/dungeon.h ../include/engrave.h ../include/flag.h \
 	../include/hack.h ../include/lint.h ../include/mextra.h \
+	../include/mcastu.h \
 	../include/mkroom.h ../include/monattk.h ../include/mondata.h \
 	../include/monflag.h ../include/monst.h ../include/monsters.h \
 	../include/nhlua.h ../include/obj.h ../include/objclass.h \
diff --git a/sys/windows/Makefile.nmake b/sys/windows/Makefile.nmake
index 044fb9e70..5a549d3ef 100644
--- a/sys/windows/Makefile.nmake
+++ b/sys/windows/Makefile.nmake
@@ -694,6 +694,7 @@ HACKINCL = \
 	$(INCL)flag.h       $(INCL)fnamesiz.h $(INCL)func_tab.h \
 	$(INCL)global.h     $(INCL)warnings.h $(INCL)hack.h \
 	$(INCL)lint.h       $(INCL)mextra.h   $(INCL)micro.h \
+	$(INCL)mcastu.h \
 	$(INCL)mfndpos.h    $(INCL)mkroom.h   $(INCL)monattk.h \
 	$(INCL)mondata.h    $(INCL)monflag.h  $(INCL)monst.h \
 	$(INCL)monsters.h   $(INCL)nhmd4.h    $(INCL)obj.h \
@@ -1131,6 +1132,7 @@ HACK_H = $(CONFIG_H) $(INCL)align.h $(INCL)artilist.h \
 	$(INCL)decl.h $(INCL)defsym.h $(INCL)display.h \
 	$(INCL)dungeon.h $(INCL)engrave.h $(INCL)flag.h \
 	$(INCL)hack.h $(INCL)lint.h $(INCL)mextra.h \
+	$(INCL)mcastu.h \
 	$(INCL)mkroom.h $(INCL)monattk.h $(INCL)mondata.h \
 	$(INCL)monflag.h $(INCL)monst.h $(INCL)monsters.h \
 	$(INCL)nhlua.h $(INCL)obj.h $(INCL)objclass.h \
@@ -2664,7 +2666,7 @@ CTAGDEP = $(INCL)align.h  $(INCL)artifact.h $(INCL)artilist.h \
 	  $(INCL)attrib.h $(INCL)context.h  $(INCL)coord.h    \
 	  $(INCL)decl.h   $(INCL)dungeon.h  $(INCL)engrave.h  \
 	  $(INCL)flag.h   $(INCL)func_tab.h $(INCL)global.h   \
-	  $(INCL)hack.h   $(INCL)mextra.h   \
+	  $(INCL)hack.h   $(INCL)mextra.h   $(INCL)mcastu.h   \
 	  $(INCL)mkroom.h $(INCL)monst.h    \
 	  $(INCL)obj.h    $(INCL)objclass.h $(INCL)prop.h     \
 	  $(INCL)quest.h  $(INCL)rect.h     $(INCL)region.h   \
@@ -2694,6 +2696,7 @@ $(UTIL)sf.tags: $(CTAGSCMD) $(CTAGDEP)
 	$(CTAGSCMD) $(CTAGSOPT) -a -f $@ $(INCL)global.h
 	$(CTAGSCMD) $(CTAGSOPT) -a -f $@ $(INCL)hack.h
 	$(CTAGSCMD) $(CTAGSOPT) -a -f $@ $(INCL)mextra.h
+	$(CTAGSCMD) $(CTAGSOPT) -a -f $@ $(INCL)mcastu.h
 	$(CTAGSCMD) $(CTAGSOPT) -a -f $@ $(INCL)mkroom.h
 	$(CTAGSCMD) $(CTAGSOPT) -a -f $@ $(INCL)monst.h
 	$(CTAGSCMD) $(CTAGSOPT) -a -f $@ $(INCL)defsym.h
@@ -3269,7 +3272,7 @@ $(OTTY)light.o: light.c $(HACK_H)
 $(OTTY)lock.o: lock.c $(HACK_H)
 $(OTTY)mail.o: mail.c $(HACK_H) $(INCL)mail.h
 $(OTTY)makemon.o: makemon.c $(HACK_H)
-$(OTTY)mcastu.o: mcastu.c $(HACK_H)
+$(OTTY)mcastu.o: mcastu.c $(HACK_H) $(INCL)mcastu.h
 $(OTTY)mdlib.o: mdlib.c $(CONFIG_H) $(INCL)align.h \
 		$(INCL)artilist.h $(INCL)attrib.h \
 		$(INCL)context.h $(INCL)defsym.h $(INCL)dlb.h \
diff --git a/sys/windows/vs/NetHack/NetHack.vcxproj b/sys/windows/vs/NetHack/NetHack.vcxproj
index 5df071e6c..72d8986b0 100644
--- a/sys/windows/vs/NetHack/NetHack.vcxproj
+++ b/sys/windows/vs/NetHack/NetHack.vcxproj
@@ -259,6 +259,7 @@
     <ClInclude Include="$(IncDir)isaac64.h" />
     <ClInclude Include="$(IncDir)lint.h" />
     <ClInclude Include="$(IncDir)load_img.h" />
+    <ClInclude Include="$(IncDir)mcastu.h" />
     <ClInclude Include="$(IncDir)mextra.h" />
     <ClInclude Include="$(IncDir)mfndpos.h" />
     <ClInclude Include="$(IncDir)mkroom.h" />
diff --git a/sys/windows/vs/NetHackW/NetHackW.vcxproj b/sys/windows/vs/NetHackW/NetHackW.vcxproj
index df43cdd0c..ba3b21b1e 100644
--- a/sys/windows/vs/NetHackW/NetHackW.vcxproj
+++ b/sys/windows/vs/NetHackW/NetHackW.vcxproj
@@ -327,6 +327,7 @@
     <ClInclude Include="$(IncDir)lint.h" />
     <ClInclude Include="$(IncDir)load_img.h" />
     <ClInclude Include="$(IncDir)mail.h" />
+    <ClInclude Include="$(IncDir)mcastu.h" />
     <ClInclude Include="$(IncDir)mextra.h" />
     <ClInclude Include="$(IncDir)mfndpos.h" />
     <ClInclude Include="$(IncDir)micro.h" />