diff --git a/nemoguardrails/llm/cache/lfu.py b/nemoguardrails/llm/cache/lfu.py
index 2c48ecb75..755f84b17 100644
--- a/nemoguardrails/llm/cache/lfu.py
+++ b/nemoguardrails/llm/cache/lfu.py
@@ -54,7 +54,8 @@ def append(self, node: LFUNode) -> None:
         """Add node to the end of the list (before tail)."""
         node.prev = self.tail.prev
         node.next = self.tail
-        self.tail.prev.next = node
+        if self.tail.prev is not None:
+            self.tail.prev.next = node
         self.tail.prev = node
         self.size += 1
 
@@ -67,8 +68,10 @@ def pop(self, node: Optional[LFUNode] = None) -> Optional[LFUNode]:
             node = self.head.next
 
         # Remove node from the list
-        node.prev.next = node.next
-        node.next.prev = node.prev
+        if node is not None and node.prev is not None:
+            node.prev.next = node.next
+        if node is not None and node.next is not None:
+            node.next.prev = node.prev
         self.size -= 1
 
         return node
@@ -121,6 +124,7 @@ def __init__(
                 "evictions": 0,
                 "puts": 0,
                 "updates": 0,
+                "hit_rate": 0.0,
             }
 
     def _update_node_freq(self, node: LFUNode) -> None:
@@ -288,6 +292,7 @@ def reset_stats(self) -> None:
                     "evictions": 0,
                     "puts": 0,
                     "updates": 0,
+                    "hit_rate": 0.0,
                 }
 
     def _check_and_log_stats(self) -> None:
diff --git a/nemoguardrails/llm/filters.py b/nemoguardrails/llm/filters.py
index c195d5b01..a78110919 100644
--- a/nemoguardrails/llm/filters.py
+++ b/nemoguardrails/llm/filters.py
@@ -140,7 +140,7 @@ def to_messages(colang_history: str) -> List[dict]:
     # a message from the user, and the rest gets translated to messages from the assistant.
     lines = colang_history.split("\n")
 
-    bot_lines = []
+    bot_lines: list[str] = []
     for i, line in enumerate(lines):
         if line.startswith('user "'):
             # If we have bot lines in the buffer, we first add a bot message.
@@ -181,8 +181,8 @@ def to_messages_v2(colang_history: str) -> List[dict]:
     # a message from the user, and the rest gets translated to messages from the assistant.
     lines = colang_history.split("\n")
 
-    user_lines = []
-    bot_lines = []
+    user_lines: list[str] = []
+    bot_lines: list[str] = []
     for line in lines:
         if line.startswith("user action:"):
             if len(bot_lines) > 0:
@@ -275,7 +275,7 @@ def verbose_v1(colang_history: str) -> str:
     return "\n".join(lines)
 
 
-def to_chat_messages(events: List[dict]) -> str:
+def to_chat_messages(events: List[dict]) -> List[dict]:
     """Filter that turns an array of events into a sequence of user/assistant messages.
 
     Properly handles multimodal content by preserving the structure when the content
diff --git a/nemoguardrails/llm/helpers.py b/nemoguardrails/llm/helpers.py
index 04835d669..88488dcf2 100644
--- a/nemoguardrails/llm/helpers.py
+++ b/nemoguardrails/llm/helpers.py
@@ -13,18 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import List, Optional, Type, Union
+from typing import List, Optional, Type
 
 from langchain.callbacks.manager import (
     AsyncCallbackManagerForLLMRun,
     CallbackManagerForLLMRun,
 )
-from langchain_core.language_models.llms import LLM, BaseLLM
+from langchain_core.language_models.llms import LLM
 
 
-def get_llm_instance_wrapper(
-    llm_instance: Union[LLM, BaseLLM], llm_type: str
-) -> Type[LLM]:
+def get_llm_instance_wrapper(llm_instance: LLM, llm_type: str) -> Type[LLM]:
     """Wraps an LLM instance in a class that can be registered with LLMRails.
 
     This is useful to create specific types of LLMs using a generic LLM provider
@@ -47,7 +45,7 @@ def model_kwargs(self):
             These are needed to allow changes to the arguments of the LLM calls.
             """
             if hasattr(llm_instance, "model_kwargs"):
-                return llm_instance.model_kwargs
+                return llm_instance.model_kwargs  # type: ignore[attr-defined] (We check in line above)
             return {}
 
         @property
@@ -66,26 +64,29 @@ def _modify_instance_kwargs(self):
             """
 
             if hasattr(llm_instance, "model_kwargs"):
-                if isinstance(llm_instance.model_kwargs, dict):
-                    llm_instance.model_kwargs["temperature"] = self.temperature
-                    llm_instance.model_kwargs["streaming"] = self.streaming
+                model_kwargs = getattr(llm_instance, "model_kwargs")
+                if isinstance(model_kwargs, dict):
+                    model_kwargs["temperature"] = self.temperature
+                    model_kwargs["streaming"] = self.streaming
 
         def _call(
             self,
             prompt: str,
             stop: Optional[List[str]] = None,
             run_manager: Optional[CallbackManagerForLLMRun] = None,
+            **kwargs,
         ) -> str:
             self._modify_instance_kwargs()
-            return llm_instance._call(prompt, stop, run_manager)
+            return llm_instance._call(prompt, stop, run_manager, **kwargs)
 
         async def _acall(
             self,
             prompt: str,
             stop: Optional[List[str]] = None,
             run_manager: Optional[AsyncCallbackManagerForLLMRun] = None,
+            **kwargs,
         ) -> str:
             self._modify_instance_kwargs()
-            return await llm_instance._acall(prompt, stop, run_manager)
+            return await llm_instance._acall(prompt, stop, run_manager, **kwargs)
 
     return WrapperLLM
diff --git a/nemoguardrails/llm/models/initializer.py b/nemoguardrails/llm/models/initializer.py
index 09071920c..fc0f4b5d6 100644
--- a/nemoguardrails/llm/models/initializer.py
+++ b/nemoguardrails/llm/models/initializer.py
@@ -20,12 +20,15 @@
 from langchain_core.language_models import BaseChatModel
 from langchain_core.language_models.llms import BaseLLM
 
-from .langchain_initializer import ModelInitializationError, init_langchain_model
+from nemoguardrails.llm.models.langchain_initializer import (
+    ModelInitializationError,
+    init_langchain_model,
+)
 
 
-# later we can easily conver it to a class
+# later we can easily convert it to a class
 def init_llm_model(
-    model_name: Optional[str],
+    model_name: str,
     provider_name: str,
     mode: Literal["chat", "text"],
     kwargs: Dict[str, Any],
diff --git a/nemoguardrails/llm/params.py b/nemoguardrails/llm/params.py
index 7a4cf13f6..3cdf948c0 100644
--- a/nemoguardrails/llm/params.py
+++ b/nemoguardrails/llm/params.py
@@ -36,7 +36,7 @@
 
 import logging
 import warnings
-from typing import Dict, Type
+from typing import Any, Dict, Type
 
 from langchain.base_language import BaseLanguageModel
 
@@ -61,18 +61,18 @@ def __init__(self, llm: BaseLanguageModel, **kwargs):
         warnings.warn(_DEPRECATION_MESSAGE, DeprecationWarning, stacklevel=2)
         self.llm = llm
         self.altered_params = kwargs
-        self.original_params = {}
+        self.original_params: dict[str, Any] = {}
 
     def __enter__(self):
         # Here we can access and modify the global language model parameters.
-        self.original_params = {}
         for param, value in self.altered_params.items():
             if hasattr(self.llm, param):
                 self.original_params[param] = getattr(self.llm, param)
                 setattr(self.llm, param, value)
 
             elif hasattr(self.llm, "model_kwargs"):
-                if param not in self.llm.model_kwargs:
+                model_kwargs = getattr(self.llm, "model_kwargs", {})
+                if param not in model_kwargs:
                     log.warning(
                         "Parameter %s does not exist for %s. Passing to model_kwargs",
                         param,
@@ -81,9 +81,10 @@ def __enter__(self):
 
                     self.original_params[param] = None
                 else:
-                    self.original_params[param] = self.llm.model_kwargs[param]
+                    self.original_params[param] = model_kwargs[param]
 
-                self.llm.model_kwargs[param] = value
+                model_kwargs[param] = value
+                setattr(self.llm, "model_kwargs", model_kwargs)
 
             else:
                 log.warning(
@@ -92,7 +93,7 @@ def __enter__(self):
                     self.llm.__class__.__name__,
                 )
 
-    def __exit__(self, type, value, traceback):
+    def __exit__(self, exc_type, value, traceback):
         # Restore original parameters when exiting the context
         for param, value in self.original_params.items():
             if hasattr(self.llm, param):
diff --git a/nemoguardrails/llm/providers/huggingface/pipeline.py b/nemoguardrails/llm/providers/huggingface/pipeline.py
index 8745a109d..b81cafb90 100644
--- a/nemoguardrails/llm/providers/huggingface/pipeline.py
+++ b/nemoguardrails/llm/providers/huggingface/pipeline.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import asyncio
 from typing import Any, List, Optional
 
 from langchain.callbacks.manager import (
@@ -20,7 +21,25 @@
     CallbackManagerForLLMRun,
 )
 from langchain.schema.output import GenerationChunk
-from langchain_community.llms import HuggingFacePipeline
+
+# Import HuggingFacePipeline with fallbacks for different LangChain versions
+HuggingFacePipeline = None  # type: ignore[assignment]
+
+try:
+    from langchain_community.llms import (
+        HuggingFacePipeline,  # type: ignore[attr-defined,no-redef]
+    )
+except ImportError:
+    # Fallback for older versions of langchain
+    try:
+        from langchain.llms import (
+            HuggingFacePipeline,  # type: ignore[attr-defined,no-redef]
+        )
+    except ImportError:
+        # Create a dummy class if HuggingFacePipeline is not available
+        class HuggingFacePipeline:  # type: ignore[misc,no-redef]
+            def __init__(self, *args, **kwargs):
+                raise ImportError("HuggingFacePipeline is not available")
 
 
 class HuggingFacePipelineCompatible(HuggingFacePipeline):
@@ -47,12 +66,13 @@ def _call(
             )
 
         # Streaming for NeMo Guardrails is not supported in sync calls.
-        if self.model_kwargs and self.model_kwargs.get("streaming"):
-            raise Exception(
+        model_kwargs = getattr(self, "model_kwargs", {})
+        if model_kwargs and model_kwargs.get("streaming"):
+            raise NotImplementedError(
                 "Streaming mode not supported for HuggingFacePipeline in NeMo Guardrails!"
             )
 
-        llm_result = self._generate(
+        llm_result = self._generate(  # type: ignore[attr-defined]
             [prompt],
             stop=stop,
             run_manager=run_manager,
@@ -78,11 +98,12 @@ async def _acall(
             )
 
         # Handle streaming, if the flag is set
-        if self.model_kwargs and self.model_kwargs.get("streaming"):
+        model_kwargs = getattr(self, "model_kwargs", {})
+        if model_kwargs and model_kwargs.get("streaming"):
             # Retrieve the streamer object, needs to be set in model_kwargs
-            streamer = self.model_kwargs.get("streamer")
+            streamer = model_kwargs.get("streamer")
             if not streamer:
-                raise Exception(
+                raise ValueError(
                     "Cannot stream, please add HuggingFace streamer object to model_kwargs!"
                 )
 
@@ -99,7 +120,7 @@ async def _acall(
                 run_manager=run_manager,
                 **kwargs,
             )
-            loop.create_task(self._agenerate(**generation_kwargs))
+            loop.create_task(getattr(self, "_agenerate")(**generation_kwargs))
 
             # And start waiting for the chunks to come in.
             completion = ""
@@ -111,7 +132,7 @@ async def _acall(
 
             return completion
 
-        llm_result = await self._agenerate(
+        llm_result = await getattr(self, "_agenerate")(
             [prompt],
             stop=stop,
             run_manager=run_manager,
diff --git a/nemoguardrails/llm/providers/huggingface/streamers.py b/nemoguardrails/llm/providers/huggingface/streamers.py
index c163b8217..7ed5a3beb 100644
--- a/nemoguardrails/llm/providers/huggingface/streamers.py
+++ b/nemoguardrails/llm/providers/huggingface/streamers.py
@@ -14,11 +14,27 @@
 # limitations under the License.
 
 import asyncio
+from typing import TYPE_CHECKING, Optional
 
-from transformers.generation.streamers import TextStreamer
+TRANSFORMERS_AVAILABLE = True
+try:
+    from transformers.generation.streamers import (  # type: ignore[import-untyped]
+        TextStreamer,
+    )
+except ImportError:
+    # Fallback if transformers is not available
+    TRANSFORMERS_AVAILABLE = False
 
+    class TextStreamer:  # type: ignore[no-redef]
+        def __init__(self, *args, **kwargs):
+            pass
 
-class AsyncTextIteratorStreamer(TextStreamer):
+
+if TYPE_CHECKING:
+    from transformers import AutoTokenizer  # type: ignore[import-untyped]
+
+
+class AsyncTextIteratorStreamer(TextStreamer):  # type: ignore[misc]
     """
     Simple async implementation for HuggingFace Transformers streamers.
 
@@ -30,12 +46,14 @@ def __init__(
         self, tokenizer: "AutoTokenizer", skip_prompt: bool = False, **decode_kwargs
     ):
         super().__init__(tokenizer, skip_prompt, **decode_kwargs)
-        self.text_queue = asyncio.Queue()
+        self.text_queue: asyncio.Queue[str] = asyncio.Queue()
         self.stop_signal = None
-        self.loop = None
+        self.loop: Optional[asyncio.AbstractEventLoop] = None
 
     def on_finalized_text(self, text: str, stream_end: bool = False):
         """Put the new text in the queue. If the stream is ending, also put a stop signal in the queue."""
+        if self.loop is None:
+            return
         if len(text) > 0:
             asyncio.run_coroutine_threadsafe(self.text_queue.put(text), self.loop)
 
diff --git a/nemoguardrails/llm/taskmanager.py b/nemoguardrails/llm/taskmanager.py
index 49e39cc24..1cf5850bb 100644
--- a/nemoguardrails/llm/taskmanager.py
+++ b/nemoguardrails/llm/taskmanager.py
@@ -95,6 +95,8 @@ def __init__(self, config: RailsConfig):
     def _get_general_instructions(self):
         """Helper to extract the general instructions."""
         text = ""
+        if self.config.instructions is None:
+            return text
         for instruction in self.config.instructions:
             if instruction.type == "general":
                 text = instruction.content
@@ -266,7 +268,9 @@ def render_task_prompt(
             task_prompt = self._render_string(
                 prompt.content, context=context, events=events
             )
-            while len(task_prompt) > prompt.max_length:
+            while (
+                prompt.max_length is not None and len(task_prompt) > prompt.max_length
+            ):
                 if not events:
                     raise Exception(
                         f"Prompt exceeds max length of {prompt.max_length} characters even without history"
@@ -288,20 +292,27 @@ def render_task_prompt(
 
             return task_prompt
         else:
+            if prompt.messages is None:
+                return []
             task_messages = self._render_messages(
                 prompt.messages, context=context, events=events
             )
             task_prompt_length = self._get_messages_text_length(task_messages)
-            while task_prompt_length > prompt.max_length:
+            while (
+                prompt.max_length is not None and task_prompt_length > prompt.max_length
+            ):
                 if not events:
                     raise Exception(
                         f"Prompt exceeds max length of {prompt.max_length} characters even without history"
                     )
                 # Remove events from the beginning of the history until the prompt fits.
                 events = events[1:]
-                task_messages = self._render_messages(
-                    prompt.messages, context=context, events=events
-                )
+                if prompt.messages is not None:
+                    task_messages = self._render_messages(
+                        prompt.messages, context=context, events=events
+                    )
+                else:
+                    task_messages = []
                 task_prompt_length = self._get_messages_text_length(task_messages)
             return task_messages
 
diff --git a/nemoguardrails/rails/llm/llmrails.py b/nemoguardrails/rails/llm/llmrails.py
index 96647158e..187300aa2 100644
--- a/nemoguardrails/rails/llm/llmrails.py
+++ b/nemoguardrails/rails/llm/llmrails.py
@@ -458,7 +458,7 @@ def _init_llms(self):
                 (model for model in self.config.models if model.type == "main"), None
             )
 
-            if main_model:
+            if main_model and main_model.model:
                 kwargs = self._prepare_model_kwargs(main_model)
                 self.llm = init_llm_model(
                     model_name=main_model.model,
@@ -490,6 +490,9 @@ def _init_llms(self):
 
             try:
                 model_name = llm_config.model
+                if not model_name:
+                    raise ValueError("LLM Config model field not set")
+
                 provider_name = llm_config.engine
                 kwargs = self._prepare_model_kwargs(llm_config)
                 mode = llm_config.mode
diff --git a/pyproject.toml b/pyproject.toml
index 2e79e544d..5c743052e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -157,6 +157,7 @@ pyright = "^1.1.405"
 include = [
   "nemoguardrails/rails/**",
   "nemoguardrails/actions/**",
+  "nemoguardrails/llm/**",
   "nemoguardrails/embeddings/**",
   "nemoguardrails/cli/**",
   "nemoguardrails/kb/**",
@@ -165,6 +166,10 @@ include = [
   "nemoguardrails/server/**",
   "tests/test_callbacks.py",
 ]
+exclude = [
+    "nemoguardrails/llm/providers/trtllm/**",
+    "nemoguardrails/llm/providers/_langchain_nvidia_ai_endpoints_patch.py"
+]
 
 [tool.poetry.group.docs]
 optional = true