diff --git a/include/bits/assert.h b/include/bits/assert.h
deleted file mode 100644
index e415cdc80e..0000000000
--- a/include/bits/assert.h
+++ /dev/null
@@ -1,11 +0,0 @@
-// Do not use include guard, to ensure assert is always defined
-#ifdef assert
-#undef assert
-#endif
-
-#ifdef NDEBUG
-# define assert(cond) (void) 0
-#else
-# define assert(cond) \
-  ((void)((cond) || (__assert_fail(__func__, __FILE__, __LINE__, #cond), 0)))
-#endif
diff --git a/src/header/assert/cbindgen.toml b/src/header/assert/cbindgen.toml
index 15dd851338..eea531eabd 100644
--- a/src/header/assert/cbindgen.toml
+++ b/src/header/assert/cbindgen.toml
@@ -5,7 +5,20 @@
 # features.h included for Rust never type (no return)
 sys_includes = ["features.h"]
 include_guard = "_RELIBC_ASSERT_H"
-trailer = "#include <bits/assert.h>"
+# trailer is placed outside include_guard
+trailer = """
+// Do not use include guard, to ensure assert is always defined
+#ifdef assert
+#undef assert
+#endif
+
+#ifdef NDEBUG
+# define assert(cond) (void) 0
+#else
+# define assert(cond) \
+  ((void)((cond) || (__assert_fail(__func__, __FILE__, __LINE__, #cond), 0)))
+#endif
+"""
 language = "C"
 style = "Tag"
 no_includes = true