fix(proxy): resolve model_group_alias in vertex live setup extraction

litellm/proxy/pass_through_endpoints/llm_passthrough_endpoints.py

@@ -2801,7 +2801,7 @@ def _build_vertex_live_setup_model_rewriter(
     return rewrite
 
 
-def _resolve_alias_to_upstream_model(setup_model: str, llm_router: Router | None) -> str:
+def resolve_alias_to_upstream_model(setup_model: str, llm_router: Router | None) -> str:
     """
     The Live SDK wraps whatever the caller typed as ``models/<name>``, so a gateway alias arrives prefixed
     """
@@ -2825,6 +2825,9 @@ def _resolve_alias_to_upstream_model(setup_model: str, llm_router: Router | None
     return upstream.removeprefix(f"{provider}/")
 
 
+_resolve_alias_to_upstream_model: Final = resolve_alias_to_upstream_model
+
+
 async def vertex_ai_live_websocket_passthrough(
     websocket: WebSocket,
     model: str | None = None,

litellm/proxy/pass_through_endpoints/pass_through_endpoints.py

@@ -2692,7 +2692,32 @@ async def _relay_passthrough_response_bytes(
         )
 
 
-def _extract_model_from_vertex_ai_setup(setup_response: Mapping[str, object]) -> str | None:
+def _get_proxy_router() -> litellm.Router | None:
+    try:
+        from litellm.proxy.proxy_server import llm_router
+    except (ImportError, AttributeError):
+        return None
+    else:
+        return llm_router
+
+
+def _extract_model_path_from_setup(setup_response: Mapping[str, object]) -> str | None:
+    if isinstance(setup_response, dict):
+        direct_model: Final = setup_response.get("model")
+        if isinstance(direct_model, str):
+            return direct_model
+        setup_obj: Final = setup_response.get("setup")
+        if isinstance(setup_obj, dict):
+            nested_model: Final = setup_obj.get("model")
+            if isinstance(nested_model, str):
+                return nested_model
+    return None
+
+
+def _extract_model_from_vertex_ai_setup(
+    setup_response: Mapping[str, object],
+    llm_router: litellm.Router | None = None,
+) -> str | None:
     """
     Extract the model name from Vertex AI Live setup response.
 
@@ -2703,22 +2728,26 @@ def _extract_model_from_vertex_ai_setup(setup_response: Mapping[str, object]) ->
     We extract just the model name: "gemini-2.0-flash-live-preview-04-09"
     """
     try:
-        # Handle both direct model field and nested setup.model field
-        model_path = None
-        if isinstance(setup_response, dict):
-            if "model" in setup_response:
-                model_path = setup_response["model"]
-            elif (
-                "setup" in setup_response
-                and isinstance(setup_response["setup"], dict)
-                and "model" in setup_response["setup"]
-            ):
-                model_path = setup_response["setup"]["model"]
+        model_path: Final = _extract_model_path_from_setup(setup_response)
 
-        if isinstance(model_path, str) and "/models/" in model_path:
-            # Extract the model name after the last "/models/"
-            model_name: Final = model_path.split("/models/")[-1]
-            return model_name
+        if isinstance(model_path, str):
+            if "/models/" in model_path:
+                # Extract the model name after the last "/models/"
+                model_name: Final = model_path.split("/models/")[-1]
+                return model_name
+
+            active_router: Final[litellm.Router | None] = llm_router if llm_router is not None else _get_proxy_router()
+
+            if active_router is not None:
+                from litellm.proxy.pass_through_endpoints.llm_passthrough_endpoints import (
+                    resolve_alias_to_upstream_model,
+                )
+
+                resolved: Final = resolve_alias_to_upstream_model(model_path, active_router)
+                if resolved != model_path:
+                    return resolved
+
+            return model_path.rsplit("/", 1)[-1]
     except Exception as e:
         verbose_proxy_logger.debug("Error extracting model from setup response: %s", e)
     return None

tests/pass_through_unit_tests/test_vertex_ai_live_passthrough.py

@@ -583,5 +583,55 @@ class TestVertexAILivePassthroughErrorHandling:
         assert "kwargs" in result
 
 
+def test_extract_model_from_vertex_ai_setup_with_alias() -> None:
+    from typing import Final
+
+    from litellm.proxy.pass_through_endpoints.pass_through_endpoints import (
+        _extract_model_from_vertex_ai_setup,
+    )
+
+    mock_router: Final = MagicMock()
+    mock_router.get_model_list.return_value = [
+        {
+            "model_name": "transcribe_live",
+            "litellm_params": {"model": "vertex_ai/gemini-3.5-transcribe-live-preview"},
+        }
+    ]
+
+    full_path_setup: Final = {
+        "setup": {
+            "model": "projects/my-proj/locations/us-central1/publishers/google/models/gemini-2.0-flash-exp"
+        }
+    }
+    assert _extract_model_from_vertex_ai_setup(full_path_setup) == "gemini-2.0-flash-exp"
+
+    alias_setup: Final = {"setup": {"model": "transcribe_live"}}
+    assert (
+        _extract_model_from_vertex_ai_setup(alias_setup, llm_router=mock_router)
+        == "gemini-3.5-transcribe-live-preview"
+    )
+
+    prefixed_alias_setup: Final = {"setup": {"model": "models/transcribe_live"}}
+    assert (
+        _extract_model_from_vertex_ai_setup(prefixed_alias_setup, llm_router=mock_router)
+        == "gemini-3.5-transcribe-live-preview"
+    )
+
+    direct_setup: Final = {
+        "model": "projects/my-proj/locations/us-central1/publishers/google/models/gemini-2.0-flash-exp"
+    }
+    assert _extract_model_from_vertex_ai_setup(direct_setup) == "gemini-2.0-flash-exp"
+
+    unaliased_setup: Final = {"setup": {"model": "gemini-2.0-flash-exp"}}
+    assert _extract_model_from_vertex_ai_setup(unaliased_setup) == "gemini-2.0-flash-exp"
+    assert (
+        _extract_model_from_vertex_ai_setup(unaliased_setup, llm_router=mock_router)
+        == "gemini-2.0-flash-exp"
+    )
+
+    empty_setup: Final = {}
+    assert _extract_model_from_vertex_ai_setup(empty_setup) is None
+
+
 if __name__ == "__main__":
     pytest.main([__file__])