fix: improve model availability checks

- Add has_model method to ModelsRoutingTable for checking pre-registered models
- Update check_model_availability to check model_store before provider APIs

tests/unit/providers/utils/inference/test_openai_mixin.py

@@ -44,11 +44,12 @@ def mixin():
     config = RemoteInferenceProviderConfig()
     mixin_instance = OpenAIMixinImpl(config=config)
 
-    # just enough to satisfy _get_provider_model_id calls
-    mock_model_store = MagicMock()
+    # Mock model_store with async methods
+    mock_model_store = AsyncMock()
     mock_model = MagicMock()
     mock_model.provider_resource_id = "test-provider-resource-id"
     mock_model_store.get_model = AsyncMock(return_value=mock_model)
+    mock_model_store.has_model = AsyncMock(return_value=False)  # Default to False, tests can override
     mixin_instance.model_store = mock_model_store
 
     return mixin_instance
@@ -189,6 +190,40 @@ class TestOpenAIMixinCheckModelAvailability:
 
             assert len(mixin._model_cache) == 3
 
+    async def test_check_model_availability_with_pre_registered_model(
+        self, mixin, mock_client_with_models, mock_client_context
+    ):
+        """Test that check_model_availability returns True for pre-registered models in model_store"""
+        # Mock model_store.has_model to return True for a specific model
+        mock_model_store = AsyncMock()
+        mock_model_store.has_model = AsyncMock(return_value=True)
+        mixin.model_store = mock_model_store
+
+        # Test that pre-registered model is found without calling the provider's API
+        with mock_client_context(mixin, mock_client_with_models):
+            mock_client_with_models.models.list.assert_not_called()
+            assert await mixin.check_model_availability("pre-registered-model")
+            # Should not call the provider's list_models since model was found in store
+            mock_client_with_models.models.list.assert_not_called()
+            mock_model_store.has_model.assert_called_once_with("pre-registered-model")
+
+    async def test_check_model_availability_fallback_to_provider_when_not_in_store(
+        self, mixin, mock_client_with_models, mock_client_context
+    ):
+        """Test that check_model_availability falls back to provider when model not in store"""
+        # Mock model_store.has_model to return False
+        mock_model_store = AsyncMock()
+        mock_model_store.has_model = AsyncMock(return_value=False)
+        mixin.model_store = mock_model_store
+
+        # Test that it falls back to provider's model cache
+        with mock_client_context(mixin, mock_client_with_models):
+            mock_client_with_models.models.list.assert_not_called()
+            assert await mixin.check_model_availability("some-mock-model-id")
+            # Should call the provider's list_models since model was not found in store
+            mock_client_with_models.models.list.assert_called_once()
+            mock_model_store.has_model.assert_called_once_with("some-mock-model-id")
+
 
 class TestOpenAIMixinCacheBehavior:
     """Test cases for cache behavior and edge cases"""