diff --git a/apps/api/src/services/nvidia_provider.py b/apps/api/src/services/nvidia_provider.py
index ce7a5d02..21bbdfe6 100644
--- a/apps/api/src/services/nvidia_provider.py
+++ b/apps/api/src/services/nvidia_provider.py
@@ -747,7 +747,7 @@ class NvidiaProvider:
 
                     # Prometheus
                     NVIDIA_REQUESTS_TOTAL.labels(status="success", tool_name="chat").inc()
-                    NVIDIA_LATENCY_SECONDS.labels(tool_name="chat").observe(latency_ms / 1000)
+                    NVIDIA_LATENCY_HISTOGRAM.labels(tool_name="chat").observe(latency_ms / 1000)
 
                     # Langfuse
                     langfuse_ctx.trace.generation(