diff --git a/libraries/AP_Mount/AP_Mount_Siyi.h b/libraries/AP_Mount/AP_Mount_Siyi.h
index 50caf9ba98..381b18b86e 100644
--- a/libraries/AP_Mount/AP_Mount_Siyi.h
+++ b/libraries/AP_Mount/AP_Mount_Siyi.h
@@ -209,7 +209,7 @@ private:
         GimbalMountingDirection mounting_dir;
         VideoOutputStatus video_mode;
     } GimbalConfigInfo;
-    static_assert(sizeof(GimbalConfigInfo) == 7);
+    static_assert(sizeof(GimbalConfigInfo) == 7, "GimbalConfigInfo must be 7 bytes");
 
     // camera image types (aka lens)
     enum class CameraImageType : uint8_t {
diff --git a/libraries/AP_Mount/AP_Mount_Xacti.h b/libraries/AP_Mount/AP_Mount_Xacti.h
index fc4b20db03..31a6684023 100644
--- a/libraries/AP_Mount/AP_Mount_Xacti.h
+++ b/libraries/AP_Mount/AP_Mount_Xacti.h
@@ -256,7 +256,7 @@ private:
         uint16_t apeture;                           // cameras' aperture * 100
         uint16_t iso_sensitivity;                   // camera's iso sensitivity
     } _status;                                      // latest status received
-    static_assert(sizeof(_status) == 48);           // status should be 48 bytes
+    static_assert(sizeof(_status) == 48, "status must be 48 bytes");           // status should be 48 bytes
     struct {
         uint32_t last_request_ms;                   // system time that status was last requested
         uint32_t last_error_status;                 // last error status reported to user