fix(logging): resolve model_map_value for proxy custom pricing (#31940)

* fix(logging): resolve model_map_value for proxy custom pricing

Use deployment model for standard logging cost-map lookup when the router overrides response.model to a group alias, and flush stdout when printing the payload.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(logging): add comment and test for deployment fallback in standard logging payload

Address review: explain why the metadata["deployment"] fallback is unconditional,
and add a test covering the get_standard_logging_object_payload code path.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(test): update model_map_key assertion for provider-prefixed keys

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(logging): scope base_model to model param only under custom_pricing

Passing model=base_model unconditionally caused _get_provider_for_cost_calc
to infer and prepend a provider prefix on all non-custom-pricing calls,
changing model_map_key for existing deployments. Scope it to custom_pricing=True
where the fix is actually needed.

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Mateo Wang <277851410+mateo-berri@users.noreply.github.com>

litellm/litellm_core_utils/litellm_logging.py

@@ -4722,7 +4722,7 @@ class StandardLoggingPayloadSetup:
         api_base: Optional[str] = None,
     ) -> StandardLoggingModelInformation:
         model_cost_name = _select_model_name_for_cost_calc(
-            model=None,
+            model=base_model if custom_pricing else None,
             completion_response=init_response_obj,  # type: ignore
             base_model=base_model,
             custom_pricing=custom_pricing,
@@ -5268,6 +5268,11 @@ def get_standard_logging_object_payload(
 
         ## Get model cost information ##
         base_model = _get_base_model_from_metadata(model_call_details=kwargs)
+        # The router overrides completion_response.model to the model-group alias before
+        # this payload is built, so cost-map lookup via that alias always misses.
+        # Fall back to the actual deployment model set by the router in metadata.
+        if base_model is None:
+            base_model = metadata.get("deployment")
         custom_pricing = use_custom_pricing_for_model(litellm_params=litellm_params)
         raw_response_cost = kwargs.get("response_cost")
         response_cost: float = raw_response_cost or 0.0
@@ -5389,7 +5394,7 @@ def get_standard_logging_object_payload(
 
 def emit_standard_logging_payload(payload: StandardLoggingPayload):
     if os.getenv("LITELLM_PRINT_STANDARD_LOGGING_PAYLOAD"):
-        print(json.dumps(payload, indent=4))  # noqa: T201
+        print(json.dumps(payload, indent=4), flush=True)  # noqa: T201
 
 
 def get_standard_logging_metadata(

tests/logging_callback_tests/test_standard_logging_payload.py

@@ -335,6 +335,74 @@ def test_get_model_cost_information():
     )
 
 
+def test_get_model_cost_information_custom_pricing_uses_base_model():
+    result = StandardLoggingPayloadSetup.get_model_cost_information(
+        base_model="bedrock/invoke/global.anthropic.claude-opus-4-6-v1",
+        custom_pricing=True,
+        custom_llm_provider="bedrock",
+        init_response_obj={"model": "invoke_test_claude"},
+    )
+    assert result["model_map_value"] is not None
+    assert result["model_map_key"] != "invoke_test_claude"
+
+
+def test_standard_logging_payload_uses_deployment_when_no_base_model():
+    """metadata["deployment"] is used for cost-map lookup when base_model is not set."""
+    from datetime import datetime
+
+    from litellm.litellm_core_utils.litellm_logging import (
+        Logging,
+        get_standard_logging_object_payload,
+    )
+
+    logging_obj = Logging(
+        model="invoke_test_claude",
+        messages=[{"role": "user", "content": "hi"}],
+        stream=False,
+        call_type="completion",
+        start_time=datetime.now(),
+        litellm_call_id="test-deploy-fallback",
+        function_id="test-fn",
+    )
+
+    kwargs = {
+        "model": "invoke_test_claude",
+        "messages": [{"role": "user", "content": "hi"}],
+        "custom_llm_provider": "bedrock",
+        "litellm_params": {
+            "metadata": {
+                "deployment": "bedrock/invoke/global.anthropic.claude-opus-4-6-v1",
+            },
+        },
+    }
+    mock_response = {
+        "id": "chatcmpl-deploy-test",
+        "object": "chat.completion",
+        "model": "invoke_test_claude",
+        "usage": {"prompt_tokens": 5, "completion_tokens": 10, "total_tokens": 15},
+        "choices": [
+            {
+                "index": 0,
+                "message": {"role": "assistant", "content": "hello"},
+                "finish_reason": "stop",
+            }
+        ],
+    }
+
+    payload = get_standard_logging_object_payload(
+        kwargs=kwargs,
+        init_response_obj=mock_response,
+        start_time=datetime.now(),
+        end_time=datetime.now(),
+        logging_obj=logging_obj,
+        status="success",
+    )
+
+    assert payload is not None
+    assert payload["model_map_information"]["model_map_value"] is not None
+    assert payload["model_map_information"]["model_map_key"] != "invoke_test_claude"
+
+
 def test_get_hidden_params():
     """Test get_hidden_params with different inputs"""
     # Test with None