diff --git a/bindings/python/src/smg/serve.py b/bindings/python/src/smg/serve.py
index 0603fd2e15..ee37bed8aa 100644
--- a/bindings/python/src/smg/serve.py
+++ b/bindings/python/src/smg/serve.py
@@ -363,13 +363,7 @@ def _add_trtllm_stub_args(parser: argparse.ArgumentParser) -> None:
     """
     group = parser.add_argument_group("TensorRT-LLM Options")
     group.add_argument("--model", type=str, help="Model path (HuggingFace ID or local path)")
-    group.add_argument("--tp-size", type=int, help="Tensor parallel size (overrides config file)")
-    group.add_argument(
-        "--config",
-        type=str,
-        required=False,
-        help="Config file path (YAML, optional - must contain tensor_parallel_size if provided)",
-    )
+    group.add_argument("--tp_size", type=int, help="Tensor parallel size (overrides config file)")
 
 
 BACKEND_ARG_ADDERS = {
@@ -482,7 +476,10 @@ def parse_serve_args(
     _import_backend_args(backend, parser)
     RouterArgs.add_cli_args(parser, use_router_prefix=True, exclude_host_port=True)
 
-    args = parser.parse_args(argv)
+    if backend == "trtllm":
+        args, _ = parser.parse_known_args(argv)
+    else:
+        args = parser.parse_args(argv)
     return backend, args, backend_args
 
 
diff --git a/bindings/python/tests/test_serve.py b/bindings/python/tests/test_serve.py
index 40ced714b5..c53875c0e2 100644
--- a/bindings/python/tests/test_serve.py
+++ b/bindings/python/tests/test_serve.py
@@ -158,9 +158,12 @@ class TestImportBackendArgs:
     def test_trtllm_adds_model_arg(self):
         parser = argparse.ArgumentParser()
         _import_backend_args("trtllm", parser)
-        args = parser.parse_args(["--model", "/path/to/model", "--config", "/path/to/config.yml"])
+        args, backend_args = parser.parse_known_args(
+            ["--model", "/path/to/model", "--config", "/path/to/config.yml"]
+        )
         assert args.model == "/path/to/model"
-        assert args.config == "/path/to/config.yml"
+        assert "--config" in backend_args
+        assert "/path/to/config.yml" in backend_args
 
     def test_sglang_import_error(self):
         """sglang is not installed in test env, so parser.error should be called."""
@@ -304,7 +307,7 @@ def test_two_pass_extracts_backend_first(self):
     def test_unknown_arg_rejected_in_pass2(self):
         """Unknown args should be rejected by the full parser in pass 2."""
         with pytest.raises(SystemExit):
-            parse_serve_args(["--backend", "trtllm", "--totally-unknown-flag"])
+            parse_serve_args(["--backend", "sglang", "--totally-unknown-flag"])
 
 
 # ---------------------------------------------------------------------------