Merge pull request #41018 from BerriAI/litellm_fix_model_alias_map_leak

fix(utils): keep litellm params out of provider request bodies

litellm/types/utils.py

@@ -3761,6 +3761,16 @@ all_litellm_params = (
         "model_file_id_mapping",
         "litellm_logging_obj",
         "litellm_call_id",
+        "completion_call_id",
+        "model_alias_map",
+        "custom_prompt_dict",
+        "stream_response",
+        "cost_per_query",
+        "ssl_verify",
+        "data_residency",
+        "async_call",
+        "aembedding",
+        "allm_passthrough_route",
         "_litellm_strip_stream_usage",
         "use_client",
         "id",

tests/test_litellm/test_utils.py

@@ -29,6 +29,7 @@ from litellm._logging import (
     verbose_logger,
 )
 from litellm.integrations.custom_logger import CustomLogger
+from litellm.litellm_core_utils.get_litellm_params import get_litellm_params
 from litellm.litellm_core_utils.thread_pool_executor import executor as logging_executor
 from litellm.proxy.utils import is_valid_api_key
 from litellm.types.utils import (
@@ -5389,6 +5390,26 @@ def test_websearch_interception_control_fields_never_reach_the_provider():
     assert set(WEBSEARCH_INTERNAL_CONTROL_FIELDS) <= set(all_litellm_params)
 
 
+def test_get_litellm_params_keys_never_reach_the_provider():
+    """Bridges (chat <-> Responses, agentic loop follow-ups) forward litellm_params as
+    `completion()` kwargs. Any key the param builder does not recognize is swept into
+    extra_body, and OpenAI rejects the call with `Unknown parameter: 'model_alias_map'`.
+    """
+    litellm_param_keys = frozenset(get_litellm_params()) - {"drop_params"}
+    kwargs = {
+        "a_real_provider_specific_param": 1,
+        "model_alias_map": {"alias": "gpt-5.4"},
+        **{key: "configured-value" for key in litellm_param_keys - {"model_alias_map"}},
+    }
+
+    non_default = get_non_default_completion_params(kwargs)
+
+    assert non_default == {"a_real_provider_specific_param": 1}, (
+        "litellm params leaked into the provider params: "
+        f"{sorted(set(non_default) - {'a_real_provider_specific_param'})}"
+    )
+
+
 def test_bedrock_batch_params_never_reach_the_provider():
     """A Bedrock managed-batch deployment carries aws_batch_role_arn / s3_* /
     bedrock_tags in its litellm_params, and the same deployment also serves chat.