diff --git a/.env.local b/.env.local
new file mode 100644
index 00000000..d3013934
--- /dev/null
+++ b/.env.local
@@ -0,0 +1,33 @@
+# Note: actually we do not support .env, just for reference
+# api
+API_HOST=0.0.0.0
+API_PORT=8000
+API_KEY=
+API_MODEL_NAME=gpt-3.5-turbo
+FASTAPI_ROOT_PATH=
+# general
+DISABLE_VERSION_CHECK=
+FORCE_CHECK_IMPORTS=
+FORCE_TORCHRUN=
+LLAMAFACTORY_VERBOSITY=
+USE_MODELSCOPE_HUB=
+RECORD_VRAM=
+# torchrun
+FORCE_TORCHRUN=
+MASTER_ADDR=
+MASTER_PORT=
+NNODES=
+RANK=
+NPROC_PER_NODE=
+# wandb
+WANDB_DISABLED=
+WANDB_PROJECT=huggingface
+WANDB_API_KEY=
+# gradio ui
+GRADIO_SHARE=0
+GRADIO_SERVER_NAME=0.0.0.0
+GRADIO_SERVER_PORT=
+GRADIO_ROOT_PATH=
+# reserved (do not use)
+LLAMABOARD_ENABLED=
+LLAMABOARD_WORKDIR=
diff --git a/data/README_zh.md b/data/README_zh.md
index 7d346d4b..5cfa4b80 100644
--- a/data/README_zh.md
+++ b/data/README_zh.md
@@ -298,7 +298,7 @@ KTO 数据集需要额外添加一个 `kto_tag` 列，包含 bool 类型的人
 
 多模态图像数据集需要额外添加一个 `images` 列，包含输入图像的路径。
 
-注意图片的数量必须和对话中 `<image>` 标记的数量严格一致。
+注意图片的数量必须与文本中所有 `<image>` 标记的数量严格一致。
 
 ```json
 [
@@ -339,7 +339,7 @@ KTO 数据集需要额外添加一个 `kto_tag` 列，包含 bool 类型的人
 
 多模态视频数据集需要额外添加一个 `videos` 列，包含输入视频的路径。
 
-注意视频的数量必须和对话中 `<video>` 标记的数量严格一致。
+注意视频的数量必须与文本中所有 `<video>` 标记的数量严格一致。
 
 ```json
 [
diff --git a/scripts/cal_mfu.py b/scripts/cal_mfu.py
index 0ae4dd42..03280b52 100644
--- a/scripts/cal_mfu.py
+++ b/scripts/cal_mfu.py
@@ -100,7 +100,7 @@ def compute_device_flops() -> float:
         raise NotImplementedError("Device not supported: {}.".format(device_name))
 
 
-def compute_mfu(
+def calculate_mfu(
     model_name_or_path: str,
     batch_size: int,
     seq_length: int,
@@ -111,7 +111,7 @@ def compute_mfu(
     liger_kernel: bool = False,
 ) -> float:
     r"""
-    Computes MFU for given model and hyper-params.
+    Calculates MFU for given model and hyper-params.
     Usage: python cal_mfu.py --model_name_or_path path_to_model --batch_size 1 --seq_length 1024
     """
     args = {
@@ -146,4 +146,4 @@ def compute_mfu(
 
 
 if __name__ == "__main__":
-    fire.Fire(compute_mfu)
+    fire.Fire(calculate_mfu)
diff --git a/scripts/cal_ppl.py b/scripts/cal_ppl.py
index 14b5d1ba..848aca8c 100644
--- a/scripts/cal_ppl.py
+++ b/scripts/cal_ppl.py
@@ -55,7 +55,7 @@ class PairwiseDataCollatorWithPadding(DataCollatorForSeq2Seq):
         return super().__call__(chosen_features)
 
 
-def cal_ppl(
+def calculate_ppl(
     model_name_or_path: str,
     save_name: str,
     batch_size: int = 4,
@@ -130,4 +130,4 @@ def cal_ppl(
 
 
 if __name__ == "__main__":
-    fire.Fire(cal_ppl)
+    fire.Fire(calculate_ppl)
diff --git a/src/llamafactory/__init__.py b/src/llamafactory/__init__.py
index 07b6d0ad..959a0377 100644
--- a/src/llamafactory/__init__.py
+++ b/src/llamafactory/__init__.py
@@ -36,6 +36,7 @@ Disable version checking: DISABLE_VERSION_CHECK=1
 Enable VRAM recording: RECORD_VRAM=1
 Force check imports: FORCE_CHECK_IMPORTS=1
 Force using torchrun: FORCE_TORCHRUN=1
+Set logging verbosity: LLAMAFACTORY_VERBOSITY=WARN
 Use modelscope: USE_MODELSCOPE_HUB=1
 """
 
diff --git a/src/llamafactory/api/app.py b/src/llamafactory/api/app.py
index be70a3a9..c9627e5a 100644
--- a/src/llamafactory/api/app.py
+++ b/src/llamafactory/api/app.py
@@ -12,8 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import asyncio
 import os
 from contextlib import asynccontextmanager
+from functools import partial
 from typing import Optional
 
 from typing_extensions import Annotated
@@ -50,15 +52,24 @@ if is_uvicorn_available():
     import uvicorn
 
 
+async def sweeper() -> None:
+    while True:
+        torch_gc()
+        await asyncio.sleep(300)
+
+
 @asynccontextmanager
-async def lifespan(app: "FastAPI"):  # collects GPU memory
+async def lifespan(app: "FastAPI", chat_model: "ChatModel"):  # collects GPU memory
+    if chat_model.engine_type == "huggingface":
+        asyncio.create_task(sweeper())
+
     yield
     torch_gc()
 
 
 def create_app(chat_model: "ChatModel") -> "FastAPI":
     root_path = os.environ.get("FASTAPI_ROOT_PATH", "")
-    app = FastAPI(lifespan=lifespan, root_path=root_path)
+    app = FastAPI(lifespan=partial(lifespan, chat_model=chat_model), root_path=root_path)
     app.add_middleware(
         CORSMiddleware,
         allow_origins=["*"],
@@ -66,7 +77,7 @@ def create_app(chat_model: "ChatModel") -> "FastAPI":
         allow_methods=["*"],
         allow_headers=["*"],
     )
-    api_key = os.environ.get("API_KEY")
+    api_key = os.environ.get("API_KEY", None)
     security = HTTPBearer(auto_error=False)
 
     async def verify_api_key(auth: Annotated[Optional[HTTPAuthorizationCredentials], Depends(security)]):
@@ -80,7 +91,7 @@ def create_app(chat_model: "ChatModel") -> "FastAPI":
         dependencies=[Depends(verify_api_key)],
     )
     async def list_models():
-        model_card = ModelCard(id="gpt-3.5-turbo")
+        model_card = ModelCard(id=os.environ.get("API_MODEL_NAME", "gpt-3.5-turbo"))
         return ModelList(data=[model_card])
 
     @app.post(
diff --git a/src/llamafactory/api/chat.py b/src/llamafactory/api/chat.py
index ee5c7412..34cf132a 100644
--- a/src/llamafactory/api/chat.py
+++ b/src/llamafactory/api/chat.py
@@ -52,9 +52,8 @@ if is_requests_available():
 
 
 if TYPE_CHECKING:
-    from numpy.typing import NDArray
-
     from ..chat import ChatModel
+    from ..data.mm_plugin import ImageInput
     from .protocol import ChatCompletionRequest, ScoreEvaluationRequest
 
 
@@ -70,7 +69,7 @@ ROLE_MAPPING = {
 
 def _process_request(
     request: "ChatCompletionRequest",
-) -> Tuple[List[Dict[str, str]], Optional[str], Optional[str], Optional["NDArray"]]:
+) -> Tuple[List[Dict[str, str]], Optional[str], Optional[str], Optional["ImageInput"]]:
     logger.info("==== request ====\n{}".format(json.dumps(dictify(request), indent=2, ensure_ascii=False)))
 
     if len(request.messages) == 0:
diff --git a/src/llamafactory/chat/base_engine.py b/src/llamafactory/chat/base_engine.py
index a95e0e3a..7087c4e5 100644
--- a/src/llamafactory/chat/base_engine.py
+++ b/src/llamafactory/chat/base_engine.py
@@ -35,6 +35,12 @@ class Response:
 
 
 class BaseEngine(ABC):
+    r"""
+    Base class for inference engine of chat models.
+
+    Must implements async methods: chat(), stream_chat() and get_scores().
+    """
+
     model: Union["PreTrainedModel", "AsyncLLMEngine"]
     tokenizer: "PreTrainedTokenizer"
     can_generate: bool
@@ -48,7 +54,11 @@ class BaseEngine(ABC):
         data_args: "DataArguments",
         finetuning_args: "FinetuningArguments",
         generating_args: "GeneratingArguments",
-    ) -> None: ...
+    ) -> None:
+        r"""
+        Initializes an inference engine.
+        """
+        ...
 
     @abstractmethod
     async def chat(
@@ -59,7 +69,11 @@ class BaseEngine(ABC):
         image: Optional["ImageInput"] = None,
         video: Optional["VideoInput"] = None,
         **input_kwargs,
-    ) -> List["Response"]: ...
+    ) -> List["Response"]:
+        r"""
+        Gets a list of responses of the chat model.
+        """
+        ...
 
     @abstractmethod
     async def stream_chat(
@@ -70,11 +84,19 @@ class BaseEngine(ABC):
         image: Optional["ImageInput"] = None,
         video: Optional["VideoInput"] = None,
         **input_kwargs,
-    ) -> AsyncGenerator[str, None]: ...
+    ) -> AsyncGenerator[str, None]:
+        r"""
+        Gets the response token-by-token of the chat model.
+        """
+        ...
 
     @abstractmethod
     async def get_scores(
         self,
         batch_input: List[str],
         **input_kwargs,
-    ) -> List[float]: ...
+    ) -> List[float]:
+        r"""
+        Gets a list of scores of the reward model.
+        """
+        ...
diff --git a/src/llamafactory/chat/chat_model.py b/src/llamafactory/chat/chat_model.py
index 3eb8124f..1e3aee57 100644
--- a/src/llamafactory/chat/chat_model.py
+++ b/src/llamafactory/chat/chat_model.py
@@ -37,8 +37,17 @@ def _start_background_loop(loop: "asyncio.AbstractEventLoop") -> None:
 
 
 class ChatModel:
+    r"""
+    General class for chat models. Backed by huggingface or vllm engines.
+
+    Supports both sync and async methods.
+    Sync methods: chat(), stream_chat() and get_scores().
+    Async methods: achat(), astream_chat() and aget_scores().
+    """
+
     def __init__(self, args: Optional[Dict[str, Any]] = None) -> None:
         model_args, data_args, finetuning_args, generating_args = get_infer_args(args)
+        self.engine_type = model_args.infer_backend
         if model_args.infer_backend == "huggingface":
             self.engine: "BaseEngine" = HuggingfaceEngine(model_args, data_args, finetuning_args, generating_args)
         elif model_args.infer_backend == "vllm":
@@ -59,6 +68,9 @@ class ChatModel:
         video: Optional["VideoInput"] = None,
         **input_kwargs,
     ) -> List["Response"]:
+        r"""
+        Gets a list of responses of the chat model.
+        """
         task = asyncio.run_coroutine_threadsafe(
             self.achat(messages, system, tools, image, video, **input_kwargs), self._loop
         )
@@ -73,6 +85,9 @@ class ChatModel:
         video: Optional["VideoInput"] = None,
         **input_kwargs,
     ) -> List["Response"]:
+        r"""
+        Asynchronously gets a list of responses of the chat model.
+        """
         return await self.engine.chat(messages, system, tools, image, video, **input_kwargs)
 
     def stream_chat(
@@ -84,6 +99,9 @@ class ChatModel:
         video: Optional["VideoInput"] = None,
         **input_kwargs,
     ) -> Generator[str, None, None]:
+        r"""
+        Gets the response token-by-token of the chat model.
+        """
         generator = self.astream_chat(messages, system, tools, image, video, **input_kwargs)
         while True:
             try:
@@ -101,6 +119,9 @@ class ChatModel:
         video: Optional["VideoInput"] = None,
         **input_kwargs,
     ) -> AsyncGenerator[str, None]:
+        r"""
+        Asynchronously gets the response token-by-token of the chat model.
+        """
         async for new_token in self.engine.stream_chat(messages, system, tools, image, video, **input_kwargs):
             yield new_token
 
@@ -109,6 +130,9 @@ class ChatModel:
         batch_input: List[str],
         **input_kwargs,
     ) -> List[float]:
+        r"""
+        Gets a list of scores of the reward model.
+        """
         task = asyncio.run_coroutine_threadsafe(self.aget_scores(batch_input, **input_kwargs), self._loop)
         return task.result()
 
@@ -117,6 +141,9 @@ class ChatModel:
         batch_input: List[str],
         **input_kwargs,
     ) -> List[float]:
+        r"""
+        Asynchronously gets a list of scores of the reward model.
+        """
         return await self.engine.get_scores(batch_input, **input_kwargs)
 
 
diff --git a/src/llamafactory/chat/hf_engine.py b/src/llamafactory/chat/hf_engine.py
index b1a9b078..e0755ac2 100644
--- a/src/llamafactory/chat/hf_engine.py
+++ b/src/llamafactory/chat/hf_engine.py
@@ -20,6 +20,7 @@ from typing import TYPE_CHECKING, Any, AsyncGenerator, Callable, Dict, List, Opt
 
 import torch
 from transformers import GenerationConfig, TextIteratorStreamer
+from typing_extensions import override
 
 from ..data import get_template_and_fix_tokenizer
 from ..extras.constants import IMAGE_PLACEHOLDER, VIDEO_PLACEHOLDER
@@ -271,6 +272,7 @@ class HuggingfaceEngine(BaseEngine):
 
         return scores
 
+    @override
     async def chat(
         self,
         messages: Sequence[Dict[str, str]],
@@ -301,6 +303,7 @@ class HuggingfaceEngine(BaseEngine):
             with concurrent.futures.ThreadPoolExecutor() as pool:
                 return await loop.run_in_executor(pool, self._chat, *input_args)
 
+    @override
     async def stream_chat(
         self,
         messages: Sequence[Dict[str, str]],
@@ -336,6 +339,7 @@ class HuggingfaceEngine(BaseEngine):
                     except StopAsyncIteration:
                         break
 
+    @override
     async def get_scores(
         self,
         batch_input: List[str],
diff --git a/src/llamafactory/chat/vllm_engine.py b/src/llamafactory/chat/vllm_engine.py
index 5ac26623..0e8e8b1c 100644
--- a/src/llamafactory/chat/vllm_engine.py
+++ b/src/llamafactory/chat/vllm_engine.py
@@ -15,6 +15,8 @@
 import uuid
 from typing import TYPE_CHECKING, Any, AsyncGenerator, AsyncIterator, Dict, List, Optional, Sequence, Union
 
+from typing_extensions import override
+
 from ..data import get_template_and_fix_tokenizer
 from ..extras.constants import IMAGE_PLACEHOLDER
 from ..extras.logging import get_logger
@@ -191,6 +193,7 @@ class VllmEngine(BaseEngine):
         )
         return result_generator
 
+    @override
     async def chat(
         self,
         messages: Sequence[Dict[str, str]],
@@ -218,6 +221,7 @@ class VllmEngine(BaseEngine):
 
         return results
 
+    @override
     async def stream_chat(
         self,
         messages: Sequence[Dict[str, str]],
@@ -234,6 +238,7 @@ class VllmEngine(BaseEngine):
             generated_text = result.outputs[0].text
             yield delta_text
 
+    @override
     async def get_scores(
         self,
         batch_input: List[str],
diff --git a/src/llamafactory/cli.py b/src/llamafactory/cli.py
index 48eb2898..8012d855 100644
--- a/src/llamafactory/cli.py
+++ b/src/llamafactory/cli.py
@@ -118,4 +118,4 @@ def main():
     elif command == Command.HELP:
         print(USAGE)
     else:
-        raise NotImplementedError("Unknown command: {}".format(command))
+        raise NotImplementedError("Unknown command: {}.".format(command))
diff --git a/src/llamafactory/data/data_utils.py b/src/llamafactory/data/data_utils.py
index 4666aabc..a58987eb 100644
--- a/src/llamafactory/data/data_utils.py
+++ b/src/llamafactory/data/data_utils.py
@@ -49,6 +49,9 @@ class DatasetModule(TypedDict):
 def merge_dataset(
     all_datasets: List[Union["Dataset", "IterableDataset"]], data_args: "DataArguments", seed: int
 ) -> Union["Dataset", "IterableDataset"]:
+    r"""
+    Merges multiple datasets to a unified dataset.
+    """
     if len(all_datasets) == 1:
         return all_datasets[0]
     elif data_args.mix_strategy == "concat":
@@ -67,14 +70,16 @@ def merge_dataset(
             stopping_strategy="first_exhausted" if data_args.mix_strategy.endswith("under") else "all_exhausted",
         )
     else:
-        raise ValueError("Unknown mixing strategy.")
+        raise ValueError("Unknown mixing strategy: {}.".format(data_args.mix_strategy))
 
 
 def split_dataset(
     dataset: Union["Dataset", "IterableDataset"], data_args: "DataArguments", seed: int
 ) -> "DatasetDict":
     r"""
-    Splits the dataset and returns a dataset dict containing train set (required) and validation set (optional).
+    Splits the dataset and returns a dataset dict containing train set and validation set.
+
+    Supports both map dataset and iterable dataset.
     """
     if data_args.streaming:
         dataset = dataset.shuffle(buffer_size=data_args.buffer_size, seed=seed)
diff --git a/src/llamafactory/data/formatter.py b/src/llamafactory/data/formatter.py
index 71b40789..f8b3979a 100644
--- a/src/llamafactory/data/formatter.py
+++ b/src/llamafactory/data/formatter.py
@@ -16,21 +16,36 @@ import json
 import re
 from abc import ABC, abstractmethod
 from dataclasses import dataclass, field
-from typing import List, Optional, Tuple, Union
+from typing import TYPE_CHECKING, List, Optional, Tuple, Union
+
+from typing_extensions import override
 
 from .data_utils import SLOTS
 from .tool_utils import get_tool_utils
 
 
+if TYPE_CHECKING:
+    from .tool_utils import FunctionCall
+
+
 @dataclass
 class Formatter(ABC):
     slots: SLOTS = field(default_factory=list)
     tool_format: Optional[str] = None
 
     @abstractmethod
-    def apply(self, **kwargs) -> SLOTS: ...
+    def apply(self, **kwargs) -> SLOTS:
+        r"""
+        Forms a list of slots according to the inputs to encode.
+        """
+        ...
 
-    def extract(self, content: str) -> Union[str, List[Tuple[str, str]]]:
+    def extract(self, content: str) -> Union[str, List["FunctionCall"]]:
+        r"""
+        Extract a list of tuples from the response message if using tools.
+
+        Each tuple consists of function name and function arguments.
+        """
         raise NotImplementedError
 
 
@@ -45,6 +60,7 @@ class EmptyFormatter(Formatter):
         if has_placeholder:
             raise ValueError("Empty formatter should not contain any placeholder.")
 
+    @override
     def apply(self, **kwargs) -> SLOTS:
         return self.slots
 
@@ -60,6 +76,7 @@ class StringFormatter(Formatter):
         if not has_placeholder:
             raise ValueError("A placeholder is required in the string formatter.")
 
+    @override
     def apply(self, **kwargs) -> SLOTS:
         elements = []
         for slot in self.slots:
@@ -83,6 +100,7 @@ class FunctionFormatter(Formatter):
     def __post_init__(self):
         self.slots = get_tool_utils(self.tool_format).get_function_slots() + self.slots
 
+    @override
     def apply(self, **kwargs) -> SLOTS:
         content = kwargs.pop("content")
         functions: List[Tuple[str, str]] = []
@@ -116,6 +134,7 @@ class ToolFormatter(Formatter):
     def __post_init__(self):
         self.tool_utils = get_tool_utils(self.tool_format)
 
+    @override
     def apply(self, **kwargs) -> SLOTS:
         content = kwargs.pop("content")
         try:
@@ -124,5 +143,6 @@ class ToolFormatter(Formatter):
         except json.JSONDecodeError:
             return [""]
 
-    def extract(self, content: str) -> Union[str, List[Tuple[str, str]]]:
+    @override
+    def extract(self, content: str) -> Union[str, List["FunctionCall"]]:
         return self.tool_utils.tool_extractor(content)
diff --git a/src/llamafactory/data/loader.py b/src/llamafactory/data/loader.py
index ff042f4f..362d57e9 100644
--- a/src/llamafactory/data/loader.py
+++ b/src/llamafactory/data/loader.py
@@ -48,6 +48,9 @@ def _load_single_dataset(
     data_args: "DataArguments",
     training_args: "Seq2SeqTrainingArguments",
 ) -> Union["Dataset", "IterableDataset"]:
+    r"""
+    Loads a single dataset and aligns it to the standard format.
+    """
     logger.info("Loading dataset {}...".format(dataset_attr))
     data_path, data_name, data_dir, data_files = None, None, None, None
     if dataset_attr.load_from in ["hf_hub", "ms_hub"]:
@@ -117,7 +120,7 @@ def _load_single_dataset(
 
     if dataset_attr.num_samples is not None and not data_args.streaming:
         target_num = dataset_attr.num_samples
-        indexes = np.random.permutation(len(dataset))[:target_num]
+        indexes = np.random.permutation(len(dataset))[:target_num]  # all samples should be included
         target_num -= len(indexes)
         if target_num > 0:
             expand_indexes = np.random.choice(len(dataset), target_num)
@@ -141,6 +144,9 @@ def _get_merged_dataset(
     training_args: "Seq2SeqTrainingArguments",
     stage: Literal["pt", "sft", "rm", "ppo", "kto"],
 ) -> Optional[Union["Dataset", "IterableDataset"]]:
+    r"""
+    Gets the merged datasets in the standard format.
+    """
     if dataset_names is None:
         return None
 
@@ -164,6 +170,9 @@ def _get_preprocessed_dataset(
     processor: Optional["ProcessorMixin"] = None,
     is_eval: bool = False,
 ) -> Optional[Union["Dataset", "IterableDataset"]]:
+    r"""
+    Preprocesses the dataset, including format checking and tokenization.
+    """
     if dataset is None:
         return None
 
@@ -209,6 +218,9 @@ def get_dataset(
     tokenizer: "PreTrainedTokenizer",
     processor: Optional["ProcessorMixin"] = None,
 ) -> "DatasetModule":
+    r"""
+    Gets the train dataset and optionally gets the evaluation dataset.
+    """
     # Load tokenized dataset
     if data_args.tokenized_path is not None:
         if has_tokenized_data(data_args.tokenized_path):
diff --git a/src/llamafactory/data/mm_plugin.py b/src/llamafactory/data/mm_plugin.py
index 5c683947..c109d26e 100644
--- a/src/llamafactory/data/mm_plugin.py
+++ b/src/llamafactory/data/mm_plugin.py
@@ -3,6 +3,7 @@ from io import BytesIO
 from typing import TYPE_CHECKING, Dict, List, Optional, Sequence, Tuple, TypedDict, Union
 
 import numpy as np
+from typing_extensions import override
 
 from ..extras.constants import IGNORE_INDEX, IMAGE_PLACEHOLDER, VIDEO_PLACEHOLDER
 from ..extras.packages import is_pillow_available, is_pyav_available
@@ -209,6 +210,7 @@ class BasePlugin:
 
 
 class LlavaPlugin(BasePlugin):
+    @override
     def process_messages(
         self,
         messages: Sequence[Dict[str, str]],
@@ -233,6 +235,7 @@ class LlavaPlugin(BasePlugin):
 
         return messages
 
+    @override
     def get_mm_inputs(
         self,
         images: Sequence["ImageInput"],
@@ -247,6 +250,7 @@ class LlavaPlugin(BasePlugin):
 
 
 class PaliGemmaPlugin(BasePlugin):
+    @override
     def process_messages(
         self,
         messages: Sequence[Dict[str, str]],
@@ -270,6 +274,7 @@ class PaliGemmaPlugin(BasePlugin):
 
         return messages
 
+    @override
     def process_token_ids(
         self,
         input_ids: List[int],
@@ -289,6 +294,7 @@ class PaliGemmaPlugin(BasePlugin):
 
         return input_ids, labels
 
+    @override
     def get_mm_inputs(
         self,
         images: Sequence["ImageInput"],
@@ -305,6 +311,7 @@ class PaliGemmaPlugin(BasePlugin):
 
 
 class Qwen2vlPlugin(BasePlugin):
+    @override
     def process_messages(
         self,
         messages: Sequence[Dict[str, str]],
@@ -359,6 +366,7 @@ class Qwen2vlPlugin(BasePlugin):
 
         return messages
 
+    @override
     def get_mm_inputs(
         self,
         images: Sequence["ImageInput"],
diff --git a/src/llamafactory/data/template.py b/src/llamafactory/data/template.py
index 9fcf2f16..ff5e32d2 100644
--- a/src/llamafactory/data/template.py
+++ b/src/llamafactory/data/template.py
@@ -16,6 +16,7 @@ from dataclasses import dataclass
 from typing import TYPE_CHECKING, Dict, List, Optional, Sequence, Tuple, Union
 
 from transformers.utils.versions import require_version
+from typing_extensions import override
 
 from ..extras.logging import get_logger
 from .data_utils import Role
@@ -152,6 +153,7 @@ class Template:
 
 @dataclass
 class Llama2Template(Template):
+    @override
     def _encode(
         self,
         tokenizer: "PreTrainedTokenizer",
@@ -195,7 +197,7 @@ class Llama2Template(Template):
         return encoded_messages
 
 
-TEMPLATES: Dict[str, Template] = {}
+TEMPLATES: Dict[str, "Template"] = {}
 
 
 def _register_template(
@@ -305,6 +307,9 @@ def _convert_slots_to_jinja(slots: "SLOTS", tokenizer: "PreTrainedTokenizer", pl
 
 
 def _get_jinja_template(template: "Template", tokenizer: "PreTrainedTokenizer") -> str:
+    r"""
+    Returns the jinja template.
+    """
     jinja_template = ""
 
     prefix = _convert_slots_to_jinja(template.format_prefix.apply(), tokenizer)
@@ -345,6 +350,9 @@ def _get_jinja_template(template: "Template", tokenizer: "PreTrainedTokenizer")
 
 
 def get_template_and_fix_tokenizer(tokenizer: "PreTrainedTokenizer", data_args: "DataArguments") -> "Template":
+    r"""
+    Gets chat template and fixes the tokenizer.
+    """
     if data_args.template in ["llava", "paligemma", "qwen2_vl"]:
         require_version(
             "transformers>=4.45.0.dev0", "To fix: pip install git+https://github.com/huggingface/transformers.git"
diff --git a/src/llamafactory/data/tool_utils.py b/src/llamafactory/data/tool_utils.py
index 0d7133fe..88027ba6 100644
--- a/src/llamafactory/data/tool_utils.py
+++ b/src/llamafactory/data/tool_utils.py
@@ -15,9 +15,12 @@
 import json
 import re
 from abc import ABC, abstractmethod
+from collections import namedtuple
 from dataclasses import dataclass
 from typing import Any, Dict, List, Tuple, Union
 
+from typing_extensions import override
+
 from .data_utils import SLOTS
 
 
@@ -38,26 +41,47 @@ GLM4_TOOL_PROMPT = (
 )
 
 
+FunctionCall = namedtuple("FunctionCall", ["name", "arguments"])
+
+
 @dataclass
 class ToolUtils(ABC):
-    @staticmethod
-    @abstractmethod
-    def get_function_slots() -> SLOTS: ...
+    """
+    Base class for tool utilities.
+    """
 
     @staticmethod
     @abstractmethod
-    def tool_formatter(tools: List[Dict[str, Any]]) -> str: ...
+    def get_function_slots() -> SLOTS:
+        r"""
+        Gets a list of slots corresponding to a single function call.
+        """
+        ...
 
     @staticmethod
     @abstractmethod
-    def tool_extractor(content: str) -> Union[str, List[Tuple[str, str]]]: ...
+    def tool_formatter(tools: List[Dict[str, Any]]) -> str:
+        r"""
+        Generates the system message describing all the available tools.
+        """
+        ...
+
+    @staticmethod
+    @abstractmethod
+    def tool_extractor(content: str) -> Union[str, List["FunctionCall"]]:
+        r"""
+        Extracts all the function calls from the response message.
+        """
+        ...
 
 
 class DefaultToolUtils(ToolUtils):
+    @override
     @staticmethod
     def get_function_slots() -> SLOTS:
         return ["Action: {{name}}\nAction Input: {{arguments}}\n"]
 
+    @override
     @staticmethod
     def tool_formatter(tools: List[Dict[str, Any]]) -> str:
         tool_text = ""
@@ -91,8 +115,9 @@ class DefaultToolUtils(ToolUtils):
 
         return DEFAULT_TOOL_PROMPT.format(tool_text=tool_text, tool_names=", ".join(tool_names))
 
+    @override
     @staticmethod
-    def tool_extractor(content: str) -> Union[str, List[Tuple[str, str]]]:
+    def tool_extractor(content: str) -> Union[str, List["FunctionCall"]]:
         regex = re.compile(r"Action:\s*([a-zA-Z0-9_]+)\s*Action Input:\s*(.+?)(?=\s*Action:|\s*$)", re.DOTALL)
         action_match: List[Tuple[str, str]] = re.findall(regex, content)
         if not action_match:
@@ -112,10 +137,12 @@ class DefaultToolUtils(ToolUtils):
 
 
 class GLM4ToolUtils(ToolUtils):
+    @override
     @staticmethod
     def get_function_slots() -> SLOTS:
         return ["{{name}}\n{{arguments}}"]
 
+    @override
     @staticmethod
     def tool_formatter(tools: List[Dict[str, Any]]) -> str:
         tool_text = ""
@@ -126,8 +153,9 @@ class GLM4ToolUtils(ToolUtils):
 
         return GLM4_TOOL_PROMPT.format(tool_text=tool_text)
 
+    @override
     @staticmethod
-    def tool_extractor(content: str) -> Union[str, List[Tuple[str, str]]]:
+    def tool_extractor(content: str) -> Union[str, List["FunctionCall"]]:
         if "\n" not in content:
             return content
 
diff --git a/src/llamafactory/eval/evaluator.py b/src/llamafactory/eval/evaluator.py
index fb0aa4a4..d445c992 100644
--- a/src/llamafactory/eval/evaluator.py
+++ b/src/llamafactory/eval/evaluator.py
@@ -39,7 +39,7 @@
 
 import json
 import os
-from typing import Any, Dict, List, Optional
+from typing import TYPE_CHECKING, Any, Dict, List, Optional
 
 import numpy as np
 import torch
@@ -54,6 +54,10 @@ from ..model import load_model, load_tokenizer
 from .template import get_eval_template
 
 
+if TYPE_CHECKING:
+    from numpy.typing import NDArray
+
+
 class Evaluator:
     def __init__(self, args: Optional[Dict[str, Any]] = None) -> None:
         self.model_args, self.data_args, self.eval_args, finetuning_args = get_eval_args(args)
@@ -65,7 +69,7 @@ class Evaluator:
         self.choice_inputs = [self.tokenizer.encode(ch, add_special_tokens=False)[-1] for ch in CHOICES]
 
     @torch.inference_mode()
-    def batch_inference(self, batch_input: Dict[str, torch.Tensor]) -> List[str]:
+    def batch_inference(self, batch_input: Dict[str, "torch.Tensor"]) -> List[str]:
         logits = self.model(**batch_input).logits
         lengths = torch.sum(batch_input["attention_mask"], dim=-1)
         word_probs = torch.stack([logits[i, lengths[i] - 1] for i in range(len(lengths))], dim=0)
@@ -132,7 +136,7 @@ class Evaluator:
         pbar.close()
         self._save_results(category_corrects, results)
 
-    def _save_results(self, category_corrects: Dict[str, np.ndarray], results: Dict[str, Dict[int, str]]) -> None:
+    def _save_results(self, category_corrects: Dict[str, "NDArray"], results: Dict[str, Dict[int, str]]) -> None:
         score_info = "\n".join(
             [
                 "{:>15}: {:.2f}".format(category_name, 100 * np.mean(category_correct))
diff --git a/src/llamafactory/extras/logging.py b/src/llamafactory/extras/logging.py
index 67622212..3a9515f6 100644
--- a/src/llamafactory/extras/logging.py
+++ b/src/llamafactory/extras/logging.py
@@ -1,4 +1,7 @@
-# Copyright 2024 the LlamaFactory team.
+# Copyright 2024 Optuna, HuggingFace Inc. and the LlamaFactory team.
+#
+# This code is inspired by the HuggingFace's transformers library.
+# https://github.com/huggingface/transformers/blob/v4.40.0/src/transformers/utils/logging.py
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,14 +18,21 @@
 import logging
 import os
 import sys
+import threading
 from concurrent.futures import ThreadPoolExecutor
+from typing import Optional
 
 from .constants import RUNNING_LOG
 
 
+_thread_lock = threading.RLock()
+_default_handler: Optional["logging.Handler"] = None
+_default_log_level: "logging._Level" = logging.INFO
+
+
 class LoggerHandler(logging.Handler):
     r"""
-    Logger handler used in Web UI.
+    Redirects the logging output to the logging file for LLaMA Board.
     """
 
     def __init__(self, output_dir: str) -> None:
@@ -56,27 +66,56 @@ class LoggerHandler(logging.Handler):
         return super().close()
 
 
-def get_logger(name: str) -> logging.Logger:
+def _get_default_logging_level() -> "logging._Level":
     r"""
-    Gets a standard logger with a stream hander to stdout.
+    Returns the default logging level.
     """
-    formatter = logging.Formatter(
-        fmt="%(asctime)s - %(levelname)s - %(name)s - %(message)s", datefmt="%m/%d/%Y %H:%M:%S"
-    )
-    handler = logging.StreamHandler(sys.stdout)
-    handler.setFormatter(formatter)
+    env_level_str = os.environ.get("LLAMAFACTORY_VERBOSITY", None)
+    if env_level_str:
+        if env_level_str.upper() in logging._nameToLevel:
+            return logging._nameToLevel[env_level_str.upper()]
+        else:
+            raise ValueError("Unknown logging level: {}.".format(env_level_str))
 
-    logger = logging.getLogger(name)
-    logger.setLevel(logging.INFO)
-    logger.addHandler(handler)
-
-    return logger
+    return _default_log_level
 
 
-def reset_logging() -> None:
+def _get_library_name() -> str:
+    return __name__.split(".")[0]
+
+
+def _get_library_root_logger() -> "logging.Logger":
+    return logging.getLogger(_get_library_name())
+
+
+def _configure_library_root_logger() -> None:
     r"""
-    Removes basic config of root logger. (unused in script)
+    Configures root logger using a stdout stream handler with an explicit format.
     """
-    root = logging.getLogger()
-    list(map(root.removeHandler, root.handlers))
-    list(map(root.removeFilter, root.filters))
+    global _default_handler
+
+    with _thread_lock:
+        if _default_handler:
+            return
+
+        formatter = logging.Formatter(
+            fmt="%(asctime)s - %(levelname)s - %(name)s - %(message)s",
+            datefmt="%m/%d/%Y %H:%M:%S",
+        )
+        _default_handler = logging.StreamHandler(sys.stdout)
+        _default_handler.setFormatter(formatter)
+        library_root_logger = _get_library_root_logger()
+        library_root_logger.addHandler(_default_handler)
+        library_root_logger.setLevel(_get_default_logging_level())
+        library_root_logger.propagate = False
+
+
+def get_logger(name: Optional[str] = None) -> "logging.Logger":
+    r"""
+    Returns a logger with the specified name. It it not supposed to be accessed externally.
+    """
+    if name is None:
+        name = _get_library_name()
+
+    _configure_library_root_logger()
+    return logging.getLogger(name)
diff --git a/src/llamafactory/extras/ploting.py b/src/llamafactory/extras/ploting.py
index 596d55e7..ba8964fb 100644
--- a/src/llamafactory/extras/ploting.py
+++ b/src/llamafactory/extras/ploting.py
@@ -70,7 +70,7 @@ def gen_loss_plot(trainer_log: List[Dict[str, Any]]) -> "matplotlib.figure.Figur
     return fig
 
 
-def plot_loss(save_dictionary: os.PathLike, keys: List[str] = ["loss"]) -> None:
+def plot_loss(save_dictionary: str, keys: List[str] = ["loss"]) -> None:
     r"""
     Plots loss curves and saves the image.
     """
diff --git a/src/llamafactory/train/callbacks.py b/src/llamafactory/train/callbacks.py
index dc1dd0ad..69c6bf43 100644
--- a/src/llamafactory/train/callbacks.py
+++ b/src/llamafactory/train/callbacks.py
@@ -32,6 +32,7 @@ from transformers.utils import (
     WEIGHTS_NAME,
     is_safetensors_available,
 )
+from typing_extensions import override
 
 from ..extras.constants import TRAINER_LOG, V_HEAD_SAFE_WEIGHTS_NAME, V_HEAD_WEIGHTS_NAME
 from ..extras.logging import LoggerHandler, get_logger
@@ -95,6 +96,7 @@ def fix_valuehead_checkpoint(
 
 
 class FixValueHeadModelCallback(TrainerCallback):
+    @override
     def on_save(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called after a checkpoint save.
@@ -114,6 +116,7 @@ class SaveProcessorCallback(TrainerCallback):
         """
         self.processor = processor
 
+    @override
     def on_train_end(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called at the end of training.
@@ -127,6 +130,7 @@ class PissaConvertCallback(TrainerCallback):
     Initializes a callback for converting the PiSSA adapter to a normal one.
     """
 
+    @override
     def on_train_begin(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called at the beginning of training.
@@ -141,6 +145,7 @@ class PissaConvertCallback(TrainerCallback):
                 model.save_pretrained(pissa_init_dir, safe_serialization=args.save_safetensors)
                 setattr(model.peft_config["default"], "init_lora_weights", init_lora_weights)
 
+    @override
     def on_train_end(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called at the end of training.
@@ -226,6 +231,7 @@ class LogCallback(TrainerCallback):
             self.thread_pool.shutdown(wait=True)
             self.thread_pool = None
 
+    @override
     def on_init_end(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called at the end of the initialization of the `Trainer`.
@@ -238,6 +244,7 @@ class LogCallback(TrainerCallback):
             logger.warning("Previous trainer log in this folder will be deleted.")
             os.remove(os.path.join(args.output_dir, TRAINER_LOG))
 
+    @override
     def on_train_begin(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called at the beginning of training.
@@ -247,12 +254,14 @@ class LogCallback(TrainerCallback):
             self._reset(max_steps=state.max_steps)
             self._create_thread_pool(output_dir=args.output_dir)
 
+    @override
     def on_train_end(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called at the end of training.
         """
         self._close_thread_pool()
 
+    @override
     def on_substep_end(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called at the end of an substep during gradient accumulation.
@@ -261,6 +270,7 @@ class LogCallback(TrainerCallback):
             control.should_epoch_stop = True
             control.should_training_stop = True
 
+    @override
     def on_step_end(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called at the end of a training step.
@@ -269,6 +279,7 @@ class LogCallback(TrainerCallback):
             control.should_epoch_stop = True
             control.should_training_stop = True
 
+    @override
     def on_evaluate(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called after an evaluation phase.
@@ -276,6 +287,7 @@ class LogCallback(TrainerCallback):
         if not self.do_train:
             self._close_thread_pool()
 
+    @override
     def on_predict(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called after a successful prediction.
@@ -283,6 +295,7 @@ class LogCallback(TrainerCallback):
         if not self.do_train:
             self._close_thread_pool()
 
+    @override
     def on_log(self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs):
         r"""
         Event called after logging the last logs.
@@ -325,6 +338,7 @@ class LogCallback(TrainerCallback):
         if self.thread_pool is not None:
             self.thread_pool.submit(self._write_log, args.output_dir, logs)
 
+    @override
     def on_prediction_step(
         self, args: "TrainingArguments", state: "TrainerState", control: "TrainerControl", **kwargs
     ):
diff --git a/src/llamafactory/train/dpo/trainer.py b/src/llamafactory/train/dpo/trainer.py
index ae2dec6a..2a0e7705 100644
--- a/src/llamafactory/train/dpo/trainer.py
+++ b/src/llamafactory/train/dpo/trainer.py
@@ -26,6 +26,7 @@ import torch.nn.functional as F
 from transformers import Trainer
 from trl import DPOTrainer
 from trl.trainer import disable_dropout_in_model
+from typing_extensions import override
 
 from ...extras.constants import IGNORE_INDEX
 from ..callbacks import PissaConvertCallback, SaveProcessorCallback
@@ -104,11 +105,13 @@ class CustomDPOTrainer(DPOTrainer):
             self.accelerator.clip_grad_norm_ = MethodType(clip_grad_norm_old_version, self.accelerator)
             self.add_callback(BAdamCallback)
 
+    @override
     def create_optimizer(self) -> "torch.optim.Optimizer":
         if self.optimizer is None:
             self.optimizer = create_custom_optimizer(self.model, self.args, self.finetuning_args)
         return super().create_optimizer()
 
+    @override
     def create_scheduler(
         self, num_training_steps: int, optimizer: Optional["torch.optim.Optimizer"] = None
     ) -> "torch.optim.lr_scheduler.LRScheduler":
@@ -164,6 +167,7 @@ class CustomDPOTrainer(DPOTrainer):
 
         return losses, chosen_rewards, rejected_rewards
 
+    @override
     def concatenated_forward(
         self, model: "PreTrainedModel", batch: Dict[str, "torch.Tensor"]
     ) -> Tuple["torch.Tensor", "torch.Tensor", "torch.Tensor", "torch.Tensor", "torch.Tensor"]:
@@ -186,6 +190,7 @@ class CustomDPOTrainer(DPOTrainer):
         chosen_length, _ = valid_length.split(batch_size, dim=0)
         return chosen_logps, rejected_logps, chosen_logits, rejected_logits, chosen_logps / chosen_length
 
+    @override
     def compute_reference_log_probs(
         self, model: "PreTrainedModel", batch: Dict[str, "torch.Tensor"]
     ) -> Tuple[Optional["torch.Tensor"], Optional["torch.Tensor"]]:
@@ -207,6 +212,7 @@ class CustomDPOTrainer(DPOTrainer):
 
         return reference_chosen_logps, reference_rejected_logps
 
+    @override
     def get_batch_loss_metrics(
         self,
         model: "PreTrainedModel",
diff --git a/src/llamafactory/train/kto/trainer.py b/src/llamafactory/train/kto/trainer.py
index 16136d6a..f547c5aa 100644
--- a/src/llamafactory/train/kto/trainer.py
+++ b/src/llamafactory/train/kto/trainer.py
@@ -25,6 +25,7 @@ import torch
 from transformers import Trainer
 from trl import KTOTrainer
 from trl.trainer import disable_dropout_in_model
+from typing_extensions import override
 
 from ...extras.constants import IGNORE_INDEX
 from ..callbacks import SaveProcessorCallback
@@ -99,23 +100,27 @@ class CustomKTOTrainer(KTOTrainer):
             self.accelerator.clip_grad_norm_ = MethodType(clip_grad_norm_old_version, self.accelerator)
             self.add_callback(BAdamCallback)
 
+    @override
     def create_optimizer(self) -> "torch.optim.Optimizer":
         if self.optimizer is None:
             self.optimizer = create_custom_optimizer(self.model, self.args, self.finetuning_args)
         return super().create_optimizer()
 
+    @override
     def create_scheduler(
         self, num_training_steps: int, optimizer: Optional["torch.optim.Optimizer"] = None
     ) -> "torch.optim.lr_scheduler.LRScheduler":
         create_custom_scheduler(self.args, num_training_steps, optimizer)
         return super().create_scheduler(num_training_steps, optimizer)
 
+    @override
     def _get_train_sampler(self) -> Optional["torch.utils.data.Sampler"]:
         r"""
         Replaces the sequential sampler of KTO Trainer created by trl with the random sampler.
         """
         return Trainer._get_train_sampler(self)
 
+    @override
     def forward(
         self, model: "PreTrainedModel", batch: Dict[str, "torch.Tensor"], prefix: Literal["", "kl_"] = ""
     ) -> Tuple["torch.Tensor", "torch.Tensor"]:
@@ -140,6 +145,7 @@ class CustomKTOTrainer(KTOTrainer):
         logps, valid_length = get_batch_logps(logits=logits, labels=batch["{}labels".format(prefix)])
         return logps, logps / valid_length
 
+    @override
     def concatenated_forward(
         self, model: "PreTrainedModel", batch: Dict[str, "torch.Tensor"]
     ) -> Tuple["torch.Tensor", "torch.Tensor", "torch.Tensor", "torch.Tensor"]:
@@ -155,6 +161,7 @@ class CustomKTOTrainer(KTOTrainer):
         chosen_logps_avg = target_logps_avg[batch["kto_tags"]]
         return chosen_logps, rejected_logps, kl_logps, chosen_logps_avg
 
+    @override
     def compute_reference_log_probs(
         self, model: "PreTrainedModel", batch: Dict[str, "torch.Tensor"]
     ) -> Tuple["torch.Tensor", "torch.Tensor", "torch.Tensor"]:
@@ -175,6 +182,7 @@ class CustomKTOTrainer(KTOTrainer):
 
         return reference_chosen_logps, reference_rejected_logps, reference_kl_logps
 
+    @override
     def get_batch_loss_metrics(
         self,
         model: "PreTrainedModel",
diff --git a/src/llamafactory/train/ppo/trainer.py b/src/llamafactory/train/ppo/trainer.py
index eeb690ca..c8d176a1 100644
--- a/src/llamafactory/train/ppo/trainer.py
+++ b/src/llamafactory/train/ppo/trainer.py
@@ -35,6 +35,7 @@ from transformers.utils import SAFE_WEIGHTS_NAME, WEIGHTS_NAME
 from trl import PPOConfig, PPOTrainer
 from trl.core import PPODecorators, logprobs_from_logits
 from trl.models.utils import unwrap_model_for_generation
+from typing_extensions import override
 
 from ...extras.logging import get_logger
 from ...extras.misc import AverageMeter, count_parameters, get_current_device, get_logits_processor
@@ -298,6 +299,7 @@ class CustomPPOTrainer(PPOTrainer, Trainer):
 
         self.callback_handler.on_train_end(self.args, self.state, self.control)
 
+    @override
     def create_optimizer(
         self,
         model: "AutoModelForCausalLMWithValueHead",
@@ -324,6 +326,7 @@ class CustomPPOTrainer(PPOTrainer, Trainer):
 
         return optimizer
 
+    @override
     def create_scheduler(
         self, training_args: "Seq2SeqTrainingArguments", num_training_steps: int, optimizer: "torch.optim.Optimizer"
     ) -> "torch.optim.lr_scheduler.LRScheduler":
@@ -410,6 +413,7 @@ class CustomPPOTrainer(PPOTrainer, Trainer):
         rewards = values.gather(dim=-1, index=(batch["attention_mask"].sum(dim=-1, keepdim=True) - 1))
         return rewards.float().detach()  # use fp32 type
 
+    @override
     @PPODecorators.empty_device_cache()
     def batched_forward_pass(
         self,
@@ -478,6 +482,7 @@ class CustomPPOTrainer(PPOTrainer, Trainer):
             torch.cat(all_masks)[:, :-1],
         )
 
+    @override
     def save_model(self, output_dir: Optional[str] = None) -> None:
         r"""
         Saves model checkpoint.
diff --git a/src/llamafactory/train/pt/trainer.py b/src/llamafactory/train/pt/trainer.py
index 0c457b97..eebdb179 100644
--- a/src/llamafactory/train/pt/trainer.py
+++ b/src/llamafactory/train/pt/trainer.py
@@ -16,6 +16,7 @@ from types import MethodType
 from typing import TYPE_CHECKING, Optional
 
 from transformers import Trainer
+from typing_extensions import override
 
 from ...extras.logging import get_logger
 from ..callbacks import PissaConvertCallback, SaveProcessorCallback
@@ -55,11 +56,13 @@ class CustomTrainer(Trainer):
             self.accelerator.clip_grad_norm_ = MethodType(clip_grad_norm_old_version, self.accelerator)
             self.add_callback(BAdamCallback)
 
+    @override
     def create_optimizer(self) -> "torch.optim.Optimizer":
         if self.optimizer is None:
             self.optimizer = create_custom_optimizer(self.model, self.args, self.finetuning_args)
         return super().create_optimizer()
 
+    @override
     def create_scheduler(
         self, num_training_steps: int, optimizer: Optional["torch.optim.Optimizer"] = None
     ) -> "torch.optim.lr_scheduler.LRScheduler":
diff --git a/src/llamafactory/train/rm/metric.py b/src/llamafactory/train/rm/metric.py
index 7c9dfeb4..17e47cc1 100644
--- a/src/llamafactory/train/rm/metric.py
+++ b/src/llamafactory/train/rm/metric.py
@@ -26,6 +26,10 @@ if TYPE_CHECKING:
 
 @dataclass
 class ComputeAccuracy:
+    r"""
+    Computes reward accuracy and supports `batch_eval_metrics`.
+    """
+
     def _dump(self) -> Optional[Dict[str, float]]:
         result = None
         if hasattr(self, "score_dict"):
diff --git a/src/llamafactory/train/rm/trainer.py b/src/llamafactory/train/rm/trainer.py
index 9ceebbe8..8cdba156 100644
--- a/src/llamafactory/train/rm/trainer.py
+++ b/src/llamafactory/train/rm/trainer.py
@@ -22,6 +22,7 @@ from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Union
 
 import torch
 from transformers import Trainer
+from typing_extensions import override
 
 from ...extras.logging import get_logger
 from ..callbacks import FixValueHeadModelCallback, PissaConvertCallback, SaveProcessorCallback
@@ -63,17 +64,20 @@ class PairwiseTrainer(Trainer):
             self.accelerator.clip_grad_norm_ = MethodType(clip_grad_norm_old_version, self.accelerator)
             self.add_callback(BAdamCallback)
 
+    @override
     def create_optimizer(self) -> "torch.optim.Optimizer":
         if self.optimizer is None:
             self.optimizer = create_custom_optimizer(self.model, self.args, self.finetuning_args)
         return super().create_optimizer()
 
+    @override
     def create_scheduler(
         self, num_training_steps: int, optimizer: Optional["torch.optim.Optimizer"] = None
     ) -> "torch.optim.lr_scheduler.LRScheduler":
         create_custom_scheduler(self.args, num_training_steps, optimizer)
         return super().create_scheduler(num_training_steps, optimizer)
 
+    @override
     def compute_loss(
         self, model: "PreTrainedModel", inputs: Dict[str, "torch.Tensor"], return_outputs: bool = False
     ) -> Union["torch.Tensor", Tuple["torch.Tensor", List["torch.Tensor"]]]:
diff --git a/src/llamafactory/train/sft/trainer.py b/src/llamafactory/train/sft/trainer.py
index 0a5c26f4..609f0f06 100644
--- a/src/llamafactory/train/sft/trainer.py
+++ b/src/llamafactory/train/sft/trainer.py
@@ -23,6 +23,7 @@ from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Union
 import numpy as np
 import torch
 from transformers import Seq2SeqTrainer
+from typing_extensions import override
 
 from ...extras.constants import IGNORE_INDEX
 from ...extras.logging import get_logger
@@ -64,17 +65,20 @@ class CustomSeq2SeqTrainer(Seq2SeqTrainer):
             self.accelerator.clip_grad_norm_ = MethodType(clip_grad_norm_old_version, self.accelerator)
             self.add_callback(BAdamCallback)
 
+    @override
     def create_optimizer(self) -> "torch.optim.Optimizer":
         if self.optimizer is None:
             self.optimizer = create_custom_optimizer(self.model, self.args, self.finetuning_args)
         return super().create_optimizer()
 
+    @override
     def create_scheduler(
         self, num_training_steps: int, optimizer: Optional["torch.optim.Optimizer"] = None
     ) -> "torch.optim.lr_scheduler.LRScheduler":
         create_custom_scheduler(self.args, num_training_steps, optimizer)
         return super().create_scheduler(num_training_steps, optimizer)
 
+    @override
     def prediction_step(
         self,
         model: "torch.nn.Module",
diff --git a/src/llamafactory/train/trainer_utils.py b/src/llamafactory/train/trainer_utils.py
index 2fa149a0..bc97e205 100644
--- a/src/llamafactory/train/trainer_utils.py
+++ b/src/llamafactory/train/trainer_utils.py
@@ -26,6 +26,7 @@ from transformers.modeling_utils import is_fsdp_enabled
 from transformers.optimization import get_scheduler
 from transformers.pytorch_utils import ALL_LAYERNORM_LAYERS
 from transformers.trainer_pt_utils import get_parameter_names
+from typing_extensions import override
 
 from ..extras.constants import IGNORE_INDEX
 from ..extras.logging import get_logger
@@ -60,9 +61,11 @@ class DummyOptimizer(torch.optim.Optimizer):
         self.optimizer_dict = optimizer_dict
         super().__init__([dummy_tensor], {"lr": lr})
 
+    @override
     def zero_grad(self, set_to_none: bool = True) -> None:
         pass
 
+    @override
     def step(self, closure: Optional[Callable[[], float]] = None) -> Optional[float]:
         pass