diff --git a/py/src/braintrust/integrations/mistral/test_mistral.py b/py/src/braintrust/integrations/mistral/test_mistral.py
index 098ff3176..f3089ae7c 100644
--- a/py/src/braintrust/integrations/mistral/test_mistral.py
+++ b/py/src/braintrust/integrations/mistral/test_mistral.py
@@ -289,7 +289,14 @@ def test_wrap_mistral_chat_complete_tool_spans(memory_logger):
     assert response.choices[0].message.tool_calls[0].function.name == "get_weather"
 
     spans = memory_logger.pop()
-    assert len(find_spans_by_type(spans, SpanTypeAttribute.LLM)) == 1
+    llm_spans = find_spans_by_type(spans, SpanTypeAttribute.LLM)
+    assert len(llm_spans) == 1
+    span = llm_spans[0]
+    service_tier = getattr(response.usage, "service_tier", None)
+    if service_tier is not None:
+        assert span["metadata"]["usage_service_tier"] == service_tier
+    else:
+        assert "usage_service_tier" not in span["metadata"]
     assert len(find_spans_by_type(spans, SpanTypeAttribute.TOOL)) == 1
 
 
diff --git a/py/src/braintrust/integrations/mistral/tracing.py b/py/src/braintrust/integrations/mistral/tracing.py
index c32305822..b8b2842ae 100644
--- a/py/src/braintrust/integrations/mistral/tracing.py
+++ b/py/src/braintrust/integrations/mistral/tracing.py
@@ -45,6 +45,7 @@ def start_span(*args, **kwargs):
 }
 _CHAT_METADATA_KEYS = (
     "model",
+    "service_tier",
     "temperature",
     "top_p",
     "max_tokens",
@@ -65,6 +66,7 @@ def start_span(*args, **kwargs):
 )
 _AGENTS_METADATA_KEYS = (
     "agent_id",
+    "service_tier",
     "max_tokens",
     "stop",
     "random_seed",
@@ -472,6 +474,11 @@ def _response_to_metadata(response: Any) -> dict[str, Any]:
         value = _get_value(response, key)
         if value is not None:
             metadata[key] = value
+
+    service_tier = _get_value(_get_value(response, "usage"), "service_tier")
+    if service_tier is not None:
+        metadata["usage_service_tier"] = service_tier
+
     return metadata