fix: skip HuggingFace download for non-llms (#4686)

Signed-off-by: Neal Vaidya <nealv@nvidia.com>

lib/bindings/python/rust/lib.rs

@@ -276,6 +276,8 @@ fn register_llm<'p>(
         ModelInput::Tensor => llm_rs::model_type::ModelInput::Tensor,
     };
 
+    let is_tensor_based = model_type.inner.supports_tensor();
+
     let model_type_obj = model_type.inner;
 
     let inner_path = model_path.to_string();
@@ -323,7 +325,33 @@ fn register_llm<'p>(
         .or_else(|| Some(source_path.clone()));
 
     pyo3_async_runtimes::tokio::future_into_py(py, async move {
-        // Resolve the model path (local or fetch from HuggingFace)
+        // For TensorBased models, skip HuggingFace downloads and register directly
+        if is_tensor_based {
+            let model_name = model_name.unwrap_or_else(|| source_path.clone());
+            let mut card = llm_rs::model_card::ModelDeploymentCard::with_name_only(&model_name);
+            card.model_type = model_type_obj;
+            card.model_input = model_input;
+            card.user_data = user_data_json;
+
+            if let Some(cfg) = runtime_config {
+                card.runtime_config = cfg.inner;
+            }
+
+            // Register the Model Deployment Card via discovery interface
+            let discovery = endpoint.inner.drt().discovery();
+            let spec = rs::discovery::DiscoverySpec::from_model(
+                endpoint.inner.component().namespace().name().to_string(),
+                endpoint.inner.component().name().to_string(),
+                endpoint.inner.name().to_string(),
+                &card,
+            )
+            .map_err(to_pyerr)?;
+            discovery.register(spec).await.map_err(to_pyerr)?;
+
+            return Ok(());
+        }
+
+        // For non-TensorBased models, resolve the model path (local or fetch from HuggingFace)
         let model_path = if fs::exists(&source_path)? {
             PathBuf::from(&source_path)
         } else {

lib/bindings/python/src/dynamo/_core.pyi

@@ -1077,6 +1077,10 @@ async def register_llm(
         Providing only one of these parameters will raise a ValueError.
         - `lora_name`: The served model name for the LoRA model
         - `base_model_path`: Path to the base model that the LoRA extends
+
+    For TensorBased models (using ModelInput.Tensor), HuggingFace downloads are skipped
+    and a minimal model card is registered directly. Use model_path as the display name
+    for these models.
     """
     ...
 

lib/bindings/python/tests/test_tensor.py

@@ -34,15 +34,12 @@ async def test_register(runtime: DistributedRuntime):
 
     assert model_config == runtime_config.get_tensor_model_config()
 
-    # [gluo FIXME] register_llm will attempt to load a LLM model,
-    # which is not well-defined for Tensor yet. Currently provide
-    # a valid model name to pass the registration.
+    # Use register_llm for tensor-based backends (skips HuggingFace downloads)
     await register_llm(
         ModelInput.Tensor,
         ModelType.TensorBased,
         endpoint,
-        "Qwen/Qwen3-0.6B",
-        "tensor",
+        "tensor",  # model_path (used as display name for tensor-based models)
         runtime_config=runtime_config,
     )
 

lib/llm/src/model_card.rs

@@ -385,6 +385,15 @@ impl ModelDeploymentCard {
             return Ok(());
         }
 
+        // For TensorBased models, config files are not used - they handle everything in the backend
+        if self.model_type.supports_tensor() {
+            tracing::debug!(
+                display_name = %self.display_name,
+                "Skipping config download for TensorBased model"
+            );
+            return Ok(());
+        }
+
         let ignore_weights = true;
         let local_path = crate::hub::from_hf(&self.display_name, ignore_weights).await?;
 

tests/frontend/grpc/echo_tensor_worker.py

@@ -53,15 +53,12 @@ async def echo_tensor_worker(runtime: DistributedRuntime):
     )
     assert model_config == retrieved_model_config
 
-    # [gluo FIXME] register_llm will attempt to load a LLM model,
-    # which is not well-defined for Tensor yet. Currently provide
-    # a valid model name to pass the registration.
+    # Use register_llm for tensor-based backends (skips HuggingFace downloads)
     await register_llm(
         ModelInput.Tensor,
         ModelType.TensorBased,
         endpoint,
-        "Qwen/Qwen3-0.6B",
-        "echo",
+        "echo",  # model_path (used as display name for tensor-based models)
         runtime_config=runtime_config,
     )