diff --git a/skynet/modules/monitoring.py b/skynet/modules/monitoring.py
index 1f792bf..095ff5a 100644
--- a/skynet/modules/monitoring.py
+++ b/skynet/modules/monitoring.py
@@ -26,6 +26,7 @@
     namespace=PROMETHEUS_NAMESPACE,
     subsystem=PROMETHEUS_SUMMARIES_SUBSYSTEM,
     buckets=[5**n for n in range(4)],
+    labelnames=['app_id'],
 )
 
 SUMMARY_FULL_DURATION_METRIC = Histogram(
diff --git a/skynet/modules/ttt/summaries/jobs.py b/skynet/modules/ttt/summaries/jobs.py
index 50cf688..c33d122 100644
--- a/skynet/modules/ttt/summaries/jobs.py
+++ b/skynet/modules/ttt/summaries/jobs.py
@@ -169,7 +169,7 @@ async def update_done_job(job: Job, result: str, processor: Processors, has_fail
     await db.lrem(RUNNING_JOBS_KEY, 0, job.id)
 
     if updated_job.status != JobStatus.SKIPPED:
-        SUMMARY_DURATION_METRIC.observe(updated_job.computed_duration, {'app_id': updated_job.metadata.app_id})
+        SUMMARY_DURATION_METRIC.labels(updated_job.metadata.app_id).observe(updated_job.computed_duration)
         SUMMARY_FULL_DURATION_METRIC.observe(updated_job.computed_full_duration)
         SUMMARY_INPUT_LENGTH_METRIC.observe(len(updated_job.payload.text))