diff --git a/source/md.h b/source/md.h
index 8ecef84..4ae8b00 100644
--- a/source/md.h
+++ b/source/md.h
@@ -195,6 +195,23 @@
 # define MD_C_LINKAGE_END }
 #endif
 
+#if MD_COMPILER_CL_YEAR >= 2005
+# include <sal.h>
+# if MD_COMPILER_CL_YEAR > 2005
+#  define MD_FORMAT_STRING_ANNOTATION _Printf_format_string_
+# else
+#  define MD_FORMAT_STRING_ANNOTATION __format_string
+# endif
+#else
+# define MD_FORMAT_STRING_ANNOTATION
+#endif
+
+#if MD_COMPILER_CLANG || MD_COMPILER_GCC
+#define MD_FORMAT_FUNCTION_ANNOTATION(str_idx, check_idx) __attribute__((format(printf, str_idx, check_idx)))
+#else
+#define MD_FORMAT_FUNCTION_ANNOTATION(str_idx, check_idx)
+#endif
+
 //~ Common defines
 
 #define MD_FUNCTION
@@ -669,7 +686,8 @@ MD_FUNCTION MD_String8     MD_FolderFromPath(MD_String8 string);
 
 MD_FUNCTION MD_String8     MD_PushStringCopy(MD_String8 string);
 MD_FUNCTION MD_String8     MD_PushStringFV(char *fmt, va_list args);
-MD_FUNCTION MD_String8     MD_PushStringF(char *fmt, ...);
+
+MD_FUNCTION MD_String8     MD_PushStringF(MD_FORMAT_STRING_ANNOTATION char *fmt, ...) MD_FORMAT_FUNCTION_ANNOTATION(1, 2);
 
 #define MD_StringExpand(s) (int)(s).size, (s).str
 
@@ -779,9 +797,9 @@ it##_r = it##_r->next, it = MD_Deref(it##_r)
 //~ Error/Warning Helpers
 
 MD_FUNCTION void MD_Message(FILE *out, MD_CodeLoc loc, MD_MessageKind kind, MD_String8 str);
-MD_FUNCTION void MD_MessageF(FILE *out, MD_CodeLoc loc, MD_MessageKind kind, char *fmt, ...);
+MD_FUNCTION void MD_MessageF(FILE *out, MD_CodeLoc loc, MD_MessageKind kind, MD_FORMAT_STRING_ANNOTATION char *fmt, ...) MD_FORMAT_FUNCTION_ANNOTATION(4, 5);
 MD_FUNCTION void MD_NodeMessage(FILE *out, MD_Node *node, MD_MessageKind kind, MD_String8 str);
-MD_FUNCTION void MD_NodeMessageF(FILE *out, MD_Node *node, MD_MessageKind kind, char *fmt, ...);
+MD_FUNCTION void MD_NodeMessageF(FILE *out, MD_Node *node, MD_MessageKind kind, MD_FORMAT_STRING_ANNOTATION char *fmt, ...) MD_FORMAT_FUNCTION_ANNOTATION(4, 5);
 
 //~ Tree Comparison/Verification
 
diff --git a/source/md_impl.c b/source/md_impl.c
index 36a62bc..db544c8 100644
--- a/source/md_impl.c
+++ b/source/md_impl.c
@@ -2295,6 +2295,7 @@ MD_Message(FILE *out, MD_CodeLoc loc, MD_MessageKind kind, MD_String8 str)
 {
     const char *kind_name = "";
     switch (kind){
+        default: break;
         case MD_MessageKind_Warning: kind_name = "warning: "; break;
         case MD_MessageKind_Error: kind_name = "error: "; break;
         case MD_MessageKind_CatastrophicError: kind_name = "fatal error: "; break;
@@ -2305,7 +2306,7 @@ MD_Message(FILE *out, MD_CodeLoc loc, MD_MessageKind kind, MD_String8 str)
 }
 
 MD_FUNCTION_IMPL void
-MD_MessageF(FILE *out, MD_CodeLoc loc, MD_MessageKind kind, char *fmt, ...)
+MD_MessageF(FILE *out, MD_CodeLoc loc, MD_MessageKind kind, MD_FORMAT_STRING_ANNOTATION char *fmt, ...) MD_FORMAT_FUNCTION_ANNOTATION(4, 5)
 {
     // TODO(allen): use scratch
     va_list args;
@@ -2322,7 +2323,7 @@ MD_NodeMessage(FILE *out, MD_Node *node, MD_MessageKind kind, MD_String8 str)
 }
 
 MD_FUNCTION_IMPL void
-MD_NodeMessageF(FILE *out, MD_Node *node, MD_MessageKind kind, char *fmt, ...)
+MD_NodeMessageF(FILE *out, MD_Node *node, MD_MessageKind kind, MD_FORMAT_STRING_ANNOTATION char *fmt, ...) MD_FORMAT_FUNCTION_ANNOTATION(4, 5)
 {
     // TODO(allen): use scratch
     va_list args;