[#20962][fix] Accept the OpenAI safety_identifier field in Chat Completions requests

tensorrt_llm/serve/openai_protocol.py

@@ -1103,6 +1103,9 @@ class ChatCompletionRequest(OpenAIBaseModel):
     # emits per turn, so parallel emission remains model behavior either way.
     parallel_tool_calls: Optional[bool] = None
     user: Optional[str] = None
+    # Standard OpenAI field, accepted for compatibility and otherwise ignored:
+    # the server does not use end-user identifiers for abuse detection.
+    safety_identifier: Optional[str] = None
     reasoning_effort: Optional[ReasoningEffort | Literal[
         "low", "medium", "high", "max", "none"]] = Field(
             default=ReasoningEffort.LOW,

tests/integration/test_lists/test-db/l0_cpu.yml

@@ -226,6 +226,7 @@ l0_cpu:
   - unittest/llmapi/apps/test_openai_chat_disagg_multimodal.py
   - unittest/llmapi/apps/test_openai_chat_multimodal_prompt.py
   - unittest/llmapi/apps/test_openai_protocol_chat_store.py
+  - unittest/llmapi/apps/test_openai_protocol_safety_identifier.py
   - unittest/llmapi/apps/test_openai_server_iteration_stats.py
   - unittest/llmapi/apps/test_reasoning_prompt_resolution.py
   - unittest/llmapi/apps/test_render_callers.py

tests/unittest/api_stability/references/trtllm_serve_api.yaml

@@ -646,6 +646,12 @@ models:
         default: null
         status: stable
         required: false
+      safety_identifier:
+        kind: openai
+        type: Optional[str]
+        default: null
+        status: stable
+        required: false
       reasoning_effort:
         kind: openai
         type: Optional[ReasoningEffort | Literal['low', 'medium', 'high', 'max', 'none']]

tests/unittest/llmapi/apps/test_openai_protocol_safety_identifier.py

@@ -0,0 +1,73 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""ChatCompletionRequest must accept the standard `safety_identifier` field.
+
+The request schema is extra="forbid", so the field must exist for requests
+from OpenAI clients that set it (it replaces the deprecated `user` field) to
+validate. The value is not used.
+"""
+
+import pytest
+from pydantic import ValidationError
+
+from tensorrt_llm.serve.openai_protocol import ChatCompletionRequest
+
+pytestmark = pytest.mark.cpu_only
+
+
+def _request(**extra) -> ChatCompletionRequest:
+    return ChatCompletionRequest(
+        model="test-model",
+        messages=[{"role": "user", "content": "hi"}],
+        **extra,
+    )
+
+
+@pytest.mark.parametrize("value", ["user-7f3a9c", ""])
+def test_safety_identifier_accepted(value):
+    req = _request(safety_identifier=value)
+    assert req.safety_identifier == value
+
+
+def test_safety_identifier_defaults_to_none():
+    assert _request().safety_identifier is None
+
+
+def test_safety_identifier_accepted_from_json():
+    req = ChatCompletionRequest.model_validate_json(
+        '{"model": "test-model", "messages": [{"role": "user", "content": "hi"}],'
+        ' "safety_identifier": "user-7f3a9c"}'
+    )
+    assert req.safety_identifier == "user-7f3a9c"
+
+
+@pytest.mark.parametrize("value", [1, ["user"], {"id": "user"}])
+def test_safety_identifier_must_be_a_string(value):
+    with pytest.raises(ValidationError):
+        _request(safety_identifier=value)
+
+
+def test_safety_identifier_leaves_other_fields_unchanged():
+    plain = _request(user="legacy-user")
+    tagged = _request(user="legacy-user", safety_identifier="user-7f3a9c")
+    assert tagged.user == "legacy-user"
+    assert tagged.model_dump(exclude={"safety_identifier"}) == plain.model_dump(
+        exclude={"safety_identifier"}
+    )
+
+
+def test_unknown_fields_remain_rejected():
+    with pytest.raises(ValidationError):
+        _request(safety_identifiers="typo")