diff --git a/tools/grib_compare.cc b/tools/grib_compare.cc
index b82377dea..dbcb8ed7e 100644
--- a/tools/grib_compare.cc
+++ b/tools/grib_compare.cc
@@ -268,8 +268,8 @@ int grib_tool_init(grib_runtime_options* options)
         options->idx     = grib_fieldset_new_from_files(context, filename,
                                                     nfiles, 0, 0, 0, orderby, &ret);
         if (ret) {
-            fprintf(stderr, "Unable to create index for input file %s (%s)",
-                    options->infile_extra->name, grib_get_error_message(ret));
+            fprintf(stderr, "%s: Unable to create index for input file %s (%s)",
+                    tool_name, options->infile_extra->name, grib_get_error_message(ret));
             exit(ret);
         }
     }
@@ -307,7 +307,7 @@ int grib_tool_init(grib_runtime_options* options)
         if (grib_options_on("R:")) {
             maxAbsoluteError = strtod(absTolStr, &endPtr);
             if (*endPtr) {
-                fprintf(stderr, "Invalid absolute error: '%s'\n", absTolStr);
+                fprintf(stderr, "%s: Invalid absolute error: '%s'\n", tool_name, absTolStr);
                 exit(1);
             }
         }
@@ -315,7 +315,7 @@ int grib_tool_init(grib_runtime_options* options)
             compare_double   = &compare_double_absolute;
             global_tolerance = strtod(absTolStr, &endPtr);
             if (*endPtr) {
-                fprintf(stderr, "Invalid absolute error: '%s'\n", absTolStr);
+                fprintf(stderr, "%s: Invalid absolute error: '%s'\n",tool_name, absTolStr);
                 exit(1);
             }
         }
diff --git a/tools/grib_copy.cc b/tools/grib_copy.cc
index 20823e2a5..ccc4c690a 100644
--- a/tools/grib_copy.cc
+++ b/tools/grib_copy.cc
@@ -104,7 +104,7 @@ int grib_tool_new_handle_action(grib_runtime_options* options, grib_handle* h)
 
         v = (double*)calloc(size, sizeof(double));
         if (!v) {
-            fprintf(stderr, "failed to allocate %ld bytes\n", (long)(size * sizeof(double)));
+            fprintf(stderr, "%s: Failed to allocate %zu bytes\n", tool_name, size * sizeof(double));
             exit(1);
         }
 
diff --git a/tools/grib_options.cc b/tools/grib_options.cc
index 6f1af95fe..78e82d1d8 100644
--- a/tools/grib_options.cc
+++ b/tools/grib_options.cc
@@ -265,7 +265,7 @@ int grib_process_runtime_options(grib_context* context, int argc, char** argv, g
         const char* optionStr = grib_options_get_option("d:");
         options->constant     = strtod(optionStr, &endPtr);
         if (*endPtr) {
-            fprintf(stderr, "Invalid number for -d option: '%s'\n", optionStr);
+            fprintf(stderr, "%s: Invalid number for -d option: '%s'\n", tool_name, optionStr);
             exit(1);
         }
         options->repack = 1;
diff --git a/tools/grib_set.cc b/tools/grib_set.cc
index 4e47264c6..13adcde65 100644
--- a/tools/grib_set.cc
+++ b/tools/grib_set.cc
@@ -76,7 +76,7 @@ int grib_tool_init(grib_runtime_options* options)
     //   }
 
     // if (grib_options_on("n:") && grib_options_on("d:")) {
-    //     fprintf(stderr, "Error: -n and -d options are incompatible. Choose one of the two please.\n");
+    //     fprintf(stderr, "%s: -n and -d options are incompatible. Choose one of the two please.\n",tool_name);
     //     exit(1);
     // }