diff --git a/mellea/formatters/granite/base/util.py b/mellea/formatters/granite/base/util.py
index 3ca3587aa..79af3ff76 100644
--- a/mellea/formatters/granite/base/util.py
+++ b/mellea/formatters/granite/base/util.py
@@ -162,9 +162,11 @@ def chat_completion_request_to_transformers_inputs(
     tokenizer_input = {
         "conversation": request["messages"],
         "add_generation_prompt": True,
-        "tools": request["tools"],
     }
 
+    if request.get("tools") is not None:
+        tokenizer_input["tools"] = request["tools"]
+
     # pylint: disable=unsupported-membership-test
     if (
         request.get("extra_body") is not None
diff --git a/pyproject.toml b/pyproject.toml
index b13604a1b..5cf8f122c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -46,7 +46,7 @@ hf = [
     "peft>=0.18.1", # Native aLoRA support added in PEFT 0.18.0
     "transformers>=4.53.2,<5",
     "trl==0.19.1",
-    "xgrammar", # Necessary for granite_common intrinsics.
+    "xgrammar==0.1.33", # Necessary for granite_common intrinsics. Pinned due to Issue 990.
     "huggingface-hub>=0.33.4",
 ]
 
diff --git a/test/backends/test_huggingface.py b/test/backends/test_huggingface.py
index 864dc0dcc..97bd6b4d4 100644
--- a/test/backends/test_huggingface.py
+++ b/test/backends/test_huggingface.py
@@ -772,13 +772,27 @@ async def test_intrinsic_streaming_raises(backend) -> None:
         )
 
 
-async def test_intrinsic_no_adapter_raises(backend) -> None:
+async def test_unknown_intrinsic_no_adapter_raises(backend) -> None:
+    """Calling an unknown intrinsic with no registered adapter raises ValueError."""
+    ctx = ChatContext().add(Message("user", "test"))
+
+    with pytest.raises(ValueError, match="Unknown intrinsic name"):
+        await mfuncs.aact(
+            Intrinsic("nonexistent_intrinsic"), ctx, backend, strategy=None
+        )
+
+
+async def test_known_intrinsic_no_adapter_raises(backend) -> None:
     """Calling an intrinsic with no registered adapter raises ValueError."""
     ctx = ChatContext().add(Message("user", "test"))
 
     with pytest.raises(ValueError, match="has no adapter"):
         await mfuncs.aact(
-            Intrinsic("nonexistent_intrinsic"), ctx, backend, strategy=None
+            # Explicitly pass in a known Intrinsic that isn't loaded.
+            Intrinsic("uncertainty"),
+            ctx,
+            backend,
+            strategy=None,
         )