diff --git a/src/measure.c b/src/measure.c
index 1018fe9..008a13b 100644
--- a/src/measure.c
+++ b/src/measure.c
@@ -174,6 +174,9 @@ void measure_summary(struct measure_params* mp, struct measure_state* ms) {
 
   sprintf(bin, "%s.bin", uuidstr);
   if ((fbin = fopen(bin, "a+")) == NULL) goto measurement_io_error;
+  size_t tlen = strlen(mp->tag);
+  if (fwrite(&tlen, sizeof(size_t), 1, fbin) != 1) goto measurement_io_error;
+  if (fwrite(mp->tag, sizeof(char), tlen, fbin) != tlen) goto measurement_io_error;
   if (fwrite(ms->uuid, sizeof(uuid_t), 1, fbin) != 1) goto measurement_io_error;
   if (fwrite(&mp->max_measure, sizeof(uint64_t), 1, fbin) != 1) goto measurement_io_error;
   if (fwrite(ms->log, sizeof(uint64_t), mp->max_measure, fbin) != mp->max_measure) goto measurement_io_error;