diff --git a/vllm/model_executor/models/interfaces.py b/vllm/model_executor/models/interfaces.py
index 749222b08470..46be838f8acc 100644
--- a/vllm/model_executor/models/interfaces.py
+++ b/vllm/model_executor/models/interfaces.py
@@ -1524,8 +1524,8 @@ def get_input_modality(
         self,
         mm_kwargs: dict[str, Any],
     ) -> str:
-        """Return the modality of the inputs."""
-        ...
+        """Return the modality of the inputs (default: image-only)."""
+        return "image"
 
     def get_max_frames_per_video(
         self,
diff --git a/vllm/model_executor/models/step3_vl.py b/vllm/model_executor/models/step3_vl.py
index 5a28ce3d004c..35a817f009d5 100644
--- a/vllm/model_executor/models/step3_vl.py
+++ b/vllm/model_executor/models/step3_vl.py
@@ -709,12 +709,6 @@ def get_encoder_cudagraph_config(self):
             out_hidden_size=self.config.hidden_size,
         )
 
-    def get_input_modality(
-        self,
-        mm_kwargs: dict[str, Any],
-    ) -> str:
-        return "image"
-
     def get_encoder_cudagraph_budget_range(
         self,
         vllm_config: "VllmConfig",