docs: add docstrings for the ModelScope download paths

The docstring coverage check flagged this diff at 25% against an 80%
threshold. Document the download helpers, the model-directory loaders in
LLM, and the ModelScope routing tests, which brings coverage of the
functions touched by this PR to 93%.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: functionstackx <47992694+functionstackx@users.noreply.github.com>

Author: functionstackx

tensorrt_llm/llmapi/llm.py

@@ -1668,6 +1668,15 @@ def _build_model(self):
         self._engine_dir, self._hf_model_dir = model_loader()
 
     def _try_load_tokenizer(self) -> Optional[TokenizerBase]:
+        """Resolve the tokenizer for this LLM instance.
+
+        Prefers an explicitly supplied tokenizer, then a single LoRA
+        directory on the PyTorch backends, and otherwise falls back to the
+        downloaded model directory or the configured model reference.
+
+        Returns:
+            The resolved tokenizer, or None when tokenizer init is skipped.
+        """
         if self.args.skip_tokenizer_init:
             return None
 
@@ -1718,6 +1727,14 @@ def tokenizer(self, tokenizer: TokenizerBase):
 
     def _try_load_generation_config(
             self) -> Optional[transformers.GenerationConfig]:
+        """Load the Hugging Face generation config for this model.
+
+        Reads from the downloaded model directory when one is available so
+        that remotely fetched snapshots are not re-resolved.
+
+        Returns:
+            The generation config, or None when the model does not ship one.
+        """
         model_dir = self._hf_model_dir or self.args.model
         return ModelLoader.load_hf_generation_config(model_dir)
 
@@ -1729,6 +1746,14 @@ def _try_load_generation_config_explicit_values(self) -> dict[str, Any]:
 
     def _try_load_hf_model_config(
             self) -> Optional[transformers.PretrainedConfig]:
+        """Load the Hugging Face model config for this model.
+
+        Reads from the downloaded model directory when one is available so
+        that remotely fetched snapshots are not re-resolved.
+
+        Returns:
+            The model config, or None when the model does not ship one.
+        """
         model_dir = self._hf_model_dir or self.args.model
         return ModelLoader.load_hf_model_config(
             model_dir, trust_remote_code=self.args.trust_remote_code)

tensorrt_llm/llmapi/utils.py

@@ -232,6 +232,15 @@ def __init__(self, *args, **kwargs):
 
 
 def download_hf_model(model: str, revision: Optional[str] = None) -> Path:
+    """Download a full model snapshot from the configured model hub.
+
+    Args:
+        model: The model name or path.
+        revision: The revision to use for the model.
+
+    Returns:
+        The path to the downloaded model.
+    """
     ignore_patterns = ["original/**/*"]
     hub_name = "ModelScope" if use_modelscope() else "Hugging Face"
     logger.info(f"Downloading model {model} from {hub_name}")

tests/unittest/llmapi/test_utils.py

@@ -22,6 +22,12 @@
 
 
 def _stub_modelscope(monkeypatch, snapshot_download):
+    """Register a fake ``modelscope`` package exposing ``snapshot_download``.
+
+    Args:
+        monkeypatch: The pytest monkeypatch fixture.
+        snapshot_download: The callable to install as the hub entry point.
+    """
     modelscope = types.ModuleType("modelscope")
     hub = types.ModuleType("modelscope.hub")
     snapshot_module = types.ModuleType("modelscope.hub.snapshot_download")
@@ -33,9 +39,11 @@ def _stub_modelscope(monkeypatch, snapshot_download):
 
 
 def test_modelscope_download_maps_snapshot_filters(monkeypatch, tmp_path):
+    """Partial downloads forward allow patterns and revision to ModelScope."""
     calls = []
 
     def snapshot_download(**kwargs):
+        """Record the hub call and return the temporary snapshot path."""
         calls.append(kwargs)
         return str(tmp_path)
 
@@ -57,9 +65,11 @@ def snapshot_download(**kwargs):
 
 
 def test_modelscope_download_maps_ignored_files(monkeypatch, tmp_path):
+    """Full downloads forward the default ignore patterns to ModelScope."""
     calls = []
 
     def snapshot_download(**kwargs):
+        """Record the hub call and return the temporary snapshot path."""
         calls.append(kwargs)
         return str(tmp_path)
 
@@ -73,9 +83,11 @@ def snapshot_download(**kwargs):
 
 
 def test_hugging_face_download_remains_the_default(monkeypatch, tmp_path):
+    """Downloads route to Hugging Face when ModelScope is not enabled."""
     calls = []
 
     def snapshot_download(model, **kwargs):
+        """Record the hub call and return the temporary snapshot path."""
         calls.append((model, kwargs))
         return str(tmp_path)
 
@@ -90,6 +102,7 @@ def snapshot_download(model, **kwargs):
 
 
 def test_modelscope_download_requires_optional_dependency(monkeypatch):
+    """A missing ``modelscope`` install raises an actionable ImportError."""
     monkeypatch.setenv("TRTLLM_USE_MODELSCOPE", "true")
     monkeypatch.setitem(sys.modules, "modelscope", None)
     monkeypatch.delitem(sys.modules,