diff --git a/src/bits.h b/src/bits.h
index 8657ae47..fd36cac9 100644
--- a/src/bits.h
+++ b/src/bits.h
@@ -864,7 +864,9 @@ typedef struct MDBX_ntxn {
 /*----------------------------------------------------------------------------*/
 /* Debug and Logging stuff */
 
+#ifndef mdbx_runtime_flags /* avoid override from tools */
 extern int mdbx_runtime_flags;
+#endif
 extern MDBX_debug_func *mdbx_debug_logger;
 extern txnid_t mdbx_debug_edge;
 
diff --git a/src/tools/mdbx_chk.c b/src/tools/mdbx_chk.c
index 9ece913d..9d3b9e06 100644
--- a/src/tools/mdbx_chk.c
+++ b/src/tools/mdbx_chk.c
@@ -20,6 +20,8 @@
 #pragma warning(disable : 4996) /* The POSIX name is deprecated... */
 #endif                          /* _MSC_VER (warnings) */
 
+/* Avoid reference to mdbx_runtime_flags from assert() */
+#define mdbx_runtime_flags (~0u)
 #include "../bits.h"
 
 typedef struct flagbit {
diff --git a/src/tools/mdbx_copy.c b/src/tools/mdbx_copy.c
index 9b0c833a..f700b178 100644
--- a/src/tools/mdbx_copy.c
+++ b/src/tools/mdbx_copy.c
@@ -20,6 +20,8 @@
 #pragma warning(disable : 4996) /* The POSIX name is deprecated... */
 #endif                          /* _MSC_VER (warnings) */
 
+/* Avoid reference to mdbx_runtime_flags from assert() */
+#define mdbx_runtime_flags (~0u)
 #include "../bits.h"
 
 #if defined(_WIN32) || defined(_WIN64)
diff --git a/src/tools/mdbx_dump.c b/src/tools/mdbx_dump.c
index 07951548..8cb9c86e 100644
--- a/src/tools/mdbx_dump.c
+++ b/src/tools/mdbx_dump.c
@@ -20,7 +20,10 @@
 #pragma warning(disable : 4996) /* The POSIX name is deprecated... */
 #endif                          /* _MSC_VER (warnings) */
 
+/* Avoid reference to mdbx_runtime_flags from assert() */
+#define mdbx_runtime_flags (~0u)
 #include "../bits.h"
+
 #include <ctype.h>
 
 #define PRINT 1
diff --git a/src/tools/mdbx_load.c b/src/tools/mdbx_load.c
index 9789e83a..9c679acb 100644
--- a/src/tools/mdbx_load.c
+++ b/src/tools/mdbx_load.c
@@ -20,7 +20,10 @@
 #pragma warning(disable : 4996) /* The POSIX name is deprecated... */
 #endif                          /* _MSC_VER (warnings) */
 
+/* Avoid reference to mdbx_runtime_flags from assert() */
+#define mdbx_runtime_flags (~0u)
 #include "../bits.h"
+
 #include <ctype.h>
 
 #if defined(_WIN32) || defined(_WIN64)
diff --git a/src/tools/mdbx_stat.c b/src/tools/mdbx_stat.c
index e459121d..d4ebc2e6 100644
--- a/src/tools/mdbx_stat.c
+++ b/src/tools/mdbx_stat.c
@@ -20,6 +20,8 @@
 #pragma warning(disable : 4996) /* The POSIX name is deprecated... */
 #endif                          /* _MSC_VER (warnings) */
 
+/* Avoid reference to mdbx_runtime_flags from assert() */
+#define mdbx_runtime_flags (~0u)
 #include "../bits.h"
 
 #if defined(_WIN32) || defined(_WIN64)