Make import time faster (optional deps + delay imports) (#253)

* adapt docs

* optional in pyproject.toml

* get rid of some transformers imports

* optional transformers in models.py

* gradio, transformers, litellm

* small refacto AgentType

* merge conflicts

* mouaif

* fix tests

* AgentText no longer a str

* Add back AgentType as str/Image

* fixed for good

docs/source/en/guided_tour.md

@@ -55,6 +55,7 @@ agent.run(
 <hfoption id="Local Transformers Model">
 
 ```python
+# !pip install smolagents[transformers]
 from smolagents import CodeAgent, TransformersModel
 
 model_id = "meta-llama/Llama-3.2-3B-Instruct"
@@ -72,6 +73,7 @@ agent.run(
 To use `LiteLLMModel`, you need to set the environment variable `ANTHROPIC_API_KEY` or `OPENAI_API_KEY`, or pass `api_key` variable upon initialization.
 
 ```python
+# !pip install smolagents[litellm]
 from smolagents import CodeAgent, LiteLLMModel
 
 model = LiteLLMModel(model_id="anthropic/claude-3-5-sonnet-latest", api_key="YOUR_ANTHROPIC_API_KEY") # Could use 'gpt-4o'
@@ -85,6 +87,7 @@ agent.run(
 <hfoption id="Ollama">
 
 ```python
+# !pip install smolagents[litellm]
 from smolagents import CodeAgent, LiteLLMModel
 
 model = LiteLLMModel(

docs/source/en/reference/agents.md

@@ -55,6 +55,9 @@ Both require arguments `model` and list of tools `tools` at initialization.
 
 ### GradioUI
 
+> [!TIP]
+> You must have `gradio` installed to use the UI. Please run `pip install smolagents[gradio]` if it's not the case.
+
 [[autodoc]] GradioUI
 
 ## Models
@@ -99,6 +102,9 @@ print(model([{"role": "user", "content": "Ok!"}], stop_sequences=["great"]))
 >>> What a
 ```
 
+> [!TIP]
+> You must have `transformers` and `torch` installed on your machine. Please run `pip install smolagents[transformers]` if it's not the case.
+
 [[autodoc]] TransformersModel
 
 ### HfApiModel

docs/source/zh/guided_tour.md

@@ -61,6 +61,7 @@ agent.run(
 <hfoption id="本地Transformers模型">
 
 ```python
+# !pip install smolagents[transformers]
 from smolagents import CodeAgent, TransformersModel
 
 model_id = "meta-llama/Llama-3.2-3B-Instruct"
@@ -78,6 +79,7 @@ agent.run(
 要使用 `LiteLLMModel`，您需要设置环境变量 `ANTHROPIC_API_KEY` 或 `OPENAI_API_KEY`，或者在初始化时传递 `api_key` 变量。
 
 ```python
+# !pip install smolagents[litellm]
 from smolagents import CodeAgent, LiteLLMModel
 
 model = LiteLLMModel(model_id="anthropic/claude-3-5-sonnet-latest", api_key="YOUR_ANTHROPIC_API_KEY") # 也可以使用 'gpt-4o'
@@ -91,6 +93,7 @@ agent.run(
 <hfoption id="Ollama">
 
 ```python
+# !pip install smolagents[litellm]
 from smolagents import CodeAgent, LiteLLMModel
 
 model = LiteLLMModel(

docs/source/zh/reference/agents.md

@@ -55,6 +55,9 @@ Both require arguments `model` and list of tools `tools` at initialization.
 
 ### GradioUI
 
+> [!TIP]
+> You must have `gradio` installed to use the UI. Please run `pip install smolagents[gradio]` if it's not the case.
+
 [[autodoc]] GradioUI
 
 ## Models
@@ -99,6 +102,9 @@ print(model([{"role": "user", "content": "Ok!"}], stop_sequences=["great"]))
 >>> What a
 ```
 
+> [!TIP]
+> You must have `transformers` and `torch` installed on your machine. Please run `pip install smolagents[transformers]` if it's not the case.
+
 [[autodoc]] TransformersModel
 
 ### HfApiModel

pyproject.toml

@@ -12,14 +12,12 @@ authors = [
 readme = "README.md"
 requires-python = ">=3.10"
 dependencies = [
-  "transformers>=4.0.0",
   "requests>=2.32.3",
   "rich>=13.9.4",
   "pandas>=2.2.3",
   "jinja2>=3.1.4",
   "pillow>=11.0.0",
   "markdownify>=0.14.1",
-  "gradio>=5.8.0",
   "duckduckgo-search>=6.3.7",
   "python-dotenv>=1.0.1",
   "e2b-code-interpreter>=1.0.3",
@@ -27,12 +25,20 @@ dependencies = [
 ]
 
 [project.optional-dependencies]
-audio = [
-  "soundfile",
-]
 torch = [
   "torch",
+]
+audio = [
+  "soundfile",
+  "smolagents[torch]",
+]
+transformers = [
   "accelerate",
+  "transformers>=4.0.0",
+  "smolagents[torch]",
+]
+gradio = [
+  "gradio>=5.8.0",
 ]
 litellm = [
   "litellm>=1.55.10",
@@ -47,9 +53,12 @@ openai = [
 quality = [
   "ruff>=0.9.0",
 ]
+all = [
+  "smolagents[accelerate,audio,gradio,litellm,mcp,openai,transformers]",
+]
 test = [
   "pytest>=8.1.0",
-  "smolagents[audio,litellm,mcp,openai,torch]",
+  "smolagents[all]",
 ]
 dev = [
   "smolagents[quality,test]",

src/smolagents/__init__.py

@@ -16,13 +16,6 @@
 # limitations under the License.
 __version__ = "1.5.0.dev"
 
-from typing import TYPE_CHECKING
-
-from transformers.utils import _LazyModule
-from transformers.utils.import_utils import define_import_structure
-
-
-if TYPE_CHECKING:
 from .agents import *
 from .default_tools import *
 from .e2b_executor import *
@@ -34,18 +27,3 @@ if TYPE_CHECKING:
 from .tools import *
 from .types import *
 from .utils import *
-
-
-else:
-    import sys
-
-    _file = globals()["__file__"]
-    import_structure = define_import_structure(_file)
-    import_structure[""] = {"__version__": __version__}
-    sys.modules[__name__] = _LazyModule(
-        __name__,
-        _file,
-        import_structure,
-        module_spec=__spec__,
-        extra_objects={"__version__": __version__},
-    )

src/smolagents/_transformers_utils.py

@@ -0,0 +1,388 @@
+#!/usr/bin/env python
+# coding=utf-8
+
+# Copyright 2025 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""This module contains utilities exclusively taken from `transformers` repository.
+
+Since they are not specific to `transformers` and that `transformers` is an heavy dependencies, those helpers have
+been duplicated.
+
+TODO: move them to `huggingface_hub` to avoid code duplication.
+"""
+
+import inspect
+import json
+import os
+import re
+import types
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    List,
+    Optional,
+    Tuple,
+    Union,
+    get_args,
+    get_origin,
+    get_type_hints,
+)
+
+from huggingface_hub.utils import is_torch_available
+
+from .utils import _is_pillow_available
+
+
+def get_imports(filename: Union[str, os.PathLike]) -> List[str]:
+    """
+    Extracts all the libraries (not relative imports this time) that are imported in a file.
+
+    Args:
+        filename (`str` or `os.PathLike`): The module file to inspect.
+
+    Returns:
+        `List[str]`: The list of all packages required to use the input module.
+    """
+    with open(filename, "r", encoding="utf-8") as f:
+        content = f.read()
+
+    # filter out try/except block so in custom code we can have try/except imports
+    content = re.sub(r"\s*try\s*:.*?except.*?:", "", content, flags=re.DOTALL)
+
+    # filter out imports under is_flash_attn_2_available block for avoid import issues in cpu only environment
+    content = re.sub(
+        r"if is_flash_attn[a-zA-Z0-9_]+available\(\):\s*(from flash_attn\s*.*\s*)+",
+        "",
+        content,
+        flags=re.MULTILINE,
+    )
+
+    # Imports of the form `import xxx`
+    imports = re.findall(r"^\s*import\s+(\S+)\s*$", content, flags=re.MULTILINE)
+    # Imports of the form `from xxx import yyy`
+    imports += re.findall(r"^\s*from\s+(\S+)\s+import", content, flags=re.MULTILINE)
+    # Only keep the top-level module
+    imports = [imp.split(".")[0] for imp in imports if not imp.startswith(".")]
+    return list(set(imports))
+
+
+class TypeHintParsingException(Exception):
+    """Exception raised for errors in parsing type hints to generate JSON schemas"""
+
+
+class DocstringParsingException(Exception):
+    """Exception raised for errors in parsing docstrings to generate JSON schemas"""
+
+
+def get_json_schema(func: Callable) -> Dict:
+    """
+    This function generates a JSON schema for a given function, based on its docstring and type hints. This is
+    mostly used for passing lists of tools to a chat template. The JSON schema contains the name and description of
+    the function, as well as the names, types and descriptions for each of its arguments. `get_json_schema()` requires
+    that the function has a docstring, and that each argument has a description in the docstring, in the standard
+    Google docstring format shown below. It also requires that all the function arguments have a valid Python type hint.
+
+    Although it is not required, a `Returns` block can also be added, which will be included in the schema. This is
+    optional because most chat templates ignore the return value of the function.
+
+    Args:
+        func: The function to generate a JSON schema for.
+
+    Returns:
+        A dictionary containing the JSON schema for the function.
+
+    Examples:
+    ```python
+    >>> def multiply(x: float, y: float):
+    >>>    '''
+    >>>    A function that multiplies two numbers
+    >>>
+    >>>    Args:
+    >>>        x: The first number to multiply
+    >>>        y: The second number to multiply
+    >>>    '''
+    >>>    return x * y
+    >>>
+    >>> print(get_json_schema(multiply))
+    {
+        "name": "multiply",
+        "description": "A function that multiplies two numbers",
+        "parameters": {
+            "type": "object",
+            "properties": {
+                "x": {"type": "number", "description": "The first number to multiply"},
+                "y": {"type": "number", "description": "The second number to multiply"}
+            },
+            "required": ["x", "y"]
+        }
+    }
+    ```
+
+    The general use for these schemas is that they are used to generate tool descriptions for chat templates that
+    support them, like so:
+
+    ```python
+    >>> from transformers import AutoTokenizer
+    >>> from transformers.utils import get_json_schema
+    >>>
+    >>> def multiply(x: float, y: float):
+    >>>    '''
+    >>>    A function that multiplies two numbers
+    >>>
+    >>>    Args:
+    >>>        x: The first number to multiply
+    >>>        y: The second number to multiply
+    >>>    return x * y
+    >>>    '''
+    >>>
+    >>> multiply_schema = get_json_schema(multiply)
+    >>> tokenizer = AutoTokenizer.from_pretrained("CohereForAI/c4ai-command-r-v01")
+    >>> messages = [{"role": "user", "content": "What is 179 x 4571?"}]
+    >>> formatted_chat = tokenizer.apply_chat_template(
+    >>>     messages,
+    >>>     tools=[multiply_schema],
+    >>>     chat_template="tool_use",
+    >>>     return_dict=True,
+    >>>     return_tensors="pt",
+    >>>     add_generation_prompt=True
+    >>> )
+    >>> # The formatted chat can now be passed to model.generate()
+    ```
+
+    Each argument description can also have an optional `(choices: ...)` block at the end, such as
+    `(choices: ["tea", "coffee"])`, which will be parsed into an `enum` field in the schema. Note that this will
+    only be parsed correctly if it is at the end of the line:
+
+    ```python
+    >>> def drink_beverage(beverage: str):
+    >>>    '''
+    >>>    A function that drinks a beverage
+    >>>
+    >>>    Args:
+    >>>        beverage: The beverage to drink (choices: ["tea", "coffee"])
+    >>>    '''
+    >>>    pass
+    >>>
+    >>> print(get_json_schema(drink_beverage))
+    ```
+    {
+        'name': 'drink_beverage',
+        'description': 'A function that drinks a beverage',
+        'parameters': {
+            'type': 'object',
+            'properties': {
+                'beverage': {
+                    'type': 'string',
+                    'enum': ['tea', 'coffee'],
+                    'description': 'The beverage to drink'
+                    }
+                },
+            'required': ['beverage']
+        }
+    }
+    """
+    doc = inspect.getdoc(func)
+    if not doc:
+        raise DocstringParsingException(
+            f"Cannot generate JSON schema for {func.__name__} because it has no docstring!"
+        )
+    doc = doc.strip()
+    main_doc, param_descriptions, return_doc = _parse_google_format_docstring(doc)
+
+    json_schema = _convert_type_hints_to_json_schema(func)
+    if (return_dict := json_schema["properties"].pop("return", None)) is not None:
+        if return_doc is not None:  # We allow a missing return docstring since most templates ignore it
+            return_dict["description"] = return_doc
+    for arg, schema in json_schema["properties"].items():
+        if arg not in param_descriptions:
+            raise DocstringParsingException(
+                f"Cannot generate JSON schema for {func.__name__} because the docstring has no description for the argument '{arg}'"
+            )
+        desc = param_descriptions[arg]
+        enum_choices = re.search(r"\(choices:\s*(.*?)\)\s*$", desc, flags=re.IGNORECASE)
+        if enum_choices:
+            schema["enum"] = [c.strip() for c in json.loads(enum_choices.group(1))]
+            desc = enum_choices.string[: enum_choices.start()].strip()
+        schema["description"] = desc
+
+    output = {"name": func.__name__, "description": main_doc, "parameters": json_schema}
+    if return_dict is not None:
+        output["return"] = return_dict
+    return {"type": "function", "function": output}
+
+
+# Extracts the initial segment of the docstring, containing the function description
+description_re = re.compile(r"^(.*?)[\n\s]*(Args:|Returns:|Raises:|\Z)", re.DOTALL)
+# Extracts the Args: block from the docstring
+args_re = re.compile(r"\n\s*Args:\n\s*(.*?)[\n\s]*(Returns:|Raises:|\Z)", re.DOTALL)
+# Splits the Args: block into individual arguments
+args_split_re = re.compile(
+    r"""
+(?:^|\n)  # Match the start of the args block, or a newline
+\s*(\w+):\s*  # Capture the argument name and strip spacing
+(.*?)\s*  # Capture the argument description, which can span multiple lines, and strip trailing spacing
+(?=\n\s*\w+:|\Z)  # Stop when you hit the next argument or the end of the block
+""",
+    re.DOTALL | re.VERBOSE,
+)
+# Extracts the Returns: block from the docstring, if present. Note that most chat templates ignore the return type/doc!
+returns_re = re.compile(r"\n\s*Returns:\n\s*(.*?)[\n\s]*(Raises:|\Z)", re.DOTALL)
+
+
+def _parse_google_format_docstring(
+    docstring: str,
+) -> Tuple[Optional[str], Optional[Dict], Optional[str]]:
+    """
+    Parses a Google-style docstring to extract the function description,
+    argument descriptions, and return description.
+
+    Args:
+        docstring (str): The docstring to parse.
+
+    Returns:
+        The function description, arguments, and return description.
+    """
+
+    # Extract the sections
+    description_match = description_re.search(docstring)
+    args_match = args_re.search(docstring)
+    returns_match = returns_re.search(docstring)
+
+    # Clean and store the sections
+    description = description_match.group(1).strip() if description_match else None
+    docstring_args = args_match.group(1).strip() if args_match else None
+    returns = returns_match.group(1).strip() if returns_match else None
+
+    # Parsing the arguments into a dictionary
+    if docstring_args is not None:
+        docstring_args = "\n".join([line for line in docstring_args.split("\n") if line.strip()])  # Remove blank lines
+        matches = args_split_re.findall(docstring_args)
+        args_dict = {match[0]: re.sub(r"\s*\n+\s*", " ", match[1].strip()) for match in matches}
+    else:
+        args_dict = {}
+
+    return description, args_dict, returns
+
+
+def _convert_type_hints_to_json_schema(func: Callable) -> Dict:
+    type_hints = get_type_hints(func)
+    signature = inspect.signature(func)
+    required = []
+    for param_name, param in signature.parameters.items():
+        if param.annotation == inspect.Parameter.empty:
+            raise TypeHintParsingException(f"Argument {param.name} is missing a type hint in function {func.__name__}")
+        if param.default == inspect.Parameter.empty:
+            required.append(param_name)
+
+    properties = {}
+    for param_name, param_type in type_hints.items():
+        properties[param_name] = _parse_type_hint(param_type)
+
+    schema = {"type": "object", "properties": properties}
+    if required:
+        schema["required"] = required
+
+    return schema
+
+
+def _parse_type_hint(hint: str) -> Dict:
+    origin = get_origin(hint)
+    args = get_args(hint)
+
+    if origin is None:
+        try:
+            return _get_json_schema_type(hint)
+        except KeyError:
+            raise TypeHintParsingException(
+                "Couldn't parse this type hint, likely due to a custom class or object: ",
+                hint,
+            )
+
+    elif origin is Union or (hasattr(types, "UnionType") and origin is types.UnionType):
+        # Recurse into each of the subtypes in the Union, except None, which is handled separately at the end
+        subtypes = [_parse_type_hint(t) for t in args if t is not type(None)]
+        if len(subtypes) == 1:
+            # A single non-null type can be expressed directly
+            return_dict = subtypes[0]
+        elif all(isinstance(subtype["type"], str) for subtype in subtypes):
+            # A union of basic types can be expressed as a list in the schema
+            return_dict = {"type": sorted([subtype["type"] for subtype in subtypes])}
+        else:
+            # A union of more complex types requires "anyOf"
+            return_dict = {"anyOf": subtypes}
+        if type(None) in args:
+            return_dict["nullable"] = True
+        return return_dict
+
+    elif origin is list:
+        if not args:
+            return {"type": "array"}
+        else:
+            # Lists can only have a single type argument, so recurse into it
+            return {"type": "array", "items": _parse_type_hint(args[0])}
+
+    elif origin is tuple:
+        if not args:
+            return {"type": "array"}
+        if len(args) == 1:
+            raise TypeHintParsingException(
+                f"The type hint {str(hint).replace('typing.', '')} is a Tuple with a single element, which "
+                "we do not automatically convert to JSON schema as it is rarely necessary. If this input can contain "
+                "more than one element, we recommend "
+                "using a List[] type instead, or if it really is a single element, remove the Tuple[] wrapper and just "
+                "pass the element directly."
+            )
+        if ... in args:
+            raise TypeHintParsingException(
+                "Conversion of '...' is not supported in Tuple type hints. "
+                "Use List[] types for variable-length"
+                " inputs instead."
+            )
+        return {"type": "array", "prefixItems": [_parse_type_hint(t) for t in args]}
+
+    elif origin is dict:
+        # The JSON equivalent to a dict is 'object', which mandates that all keys are strings
+        # However, we can specify the type of the dict values with "additionalProperties"
+        out = {"type": "object"}
+        if len(args) == 2:
+            out["additionalProperties"] = _parse_type_hint(args[1])
+        return out
+
+    raise TypeHintParsingException("Couldn't parse this type hint, likely due to a custom class or object: ", hint)
+
+
+_BASE_TYPE_MAPPING = {
+    int: {"type": "integer"},
+    float: {"type": "number"},
+    str: {"type": "string"},
+    bool: {"type": "boolean"},
+    Any: {},
+}
+
+
+def _get_json_schema_type(param_type: str) -> Dict[str, str]:
+    if param_type in _BASE_TYPE_MAPPING:
+        return _BASE_TYPE_MAPPING[param_type]
+    if str(param_type) == "Image" and _is_pillow_available():
+        from PIL.Image import Image
+
+        if param_type == Image:
+            return {"type": "image"}
+    if str(param_type) == "Tensor" and is_torch_available():
+        from torch import Tensor
+
+        if param_type == Tensor:
+            return {"type": "audio"}
+    return {"type": "object"}

src/smolagents/default_tools.py

@@ -14,33 +14,19 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import json
 import re
 from dataclasses import dataclass
 from typing import Dict, Optional
 
-from huggingface_hub import hf_hub_download, list_spaces
-from transformers.utils import is_offline_mode, is_torch_available
-
 from .local_python_executor import (
     BASE_BUILTIN_MODULES,
     BASE_PYTHON_TOOLS,
     evaluate_python_code,
 )
-from .tools import TOOL_CONFIG_FILE, PipelineTool, Tool
+from .tools import PipelineTool, Tool
 from .types import AgentAudio
 
 
-if is_torch_available():
-    from transformers.models.whisper import (
-        WhisperForConditionalGeneration,
-        WhisperProcessor,
-    )
-else:
-    WhisperForConditionalGeneration = object
-    WhisperProcessor = object
-
-
 @dataclass
 class PreTool:
     name: str
@@ -51,31 +37,6 @@ class PreTool:
     repo_id: str
 
 
-def get_remote_tools(logger, organization="huggingface-tools"):
-    if is_offline_mode():
-        logger.info("You are in offline mode, so remote tools are not available.")
-        return {}
-
-    spaces = list_spaces(author=organization)
-    tools = {}
-    for space_info in spaces:
-        repo_id = space_info.id
-        resolved_config_file = hf_hub_download(repo_id, TOOL_CONFIG_FILE, repo_type="space")
-        with open(resolved_config_file, encoding="utf-8") as reader:
-            config = json.load(reader)
-        task = repo_id.split("/")[-1]
-        tools[config["name"]] = PreTool(
-            task=task,
-            description=config["description"],
-            repo_id=repo_id,
-            name=task,
-            inputs=config["inputs"],
-            output_type=config["output_type"],
-        )
-
-    return tools
-
-
 class PythonInterpreterTool(Tool):
     name = "python_interpreter"
     description = "This is a tool that evaluates python code. It can be used to perform calculations."
@@ -150,10 +111,10 @@ class DuckDuckGoSearchTool(Tool):
         self.max_results = max_results
         try:
             from duckduckgo_search import DDGS
-        except ImportError:
+        except ImportError as e:
             raise ImportError(
                 "You must install package `duckduckgo_search` to run this tool: for instance run `pip install duckduckgo-search`."
-            )
+            ) from e
         self.ddgs = DDGS()
 
     def forward(self, query: str) -> str:
@@ -259,10 +220,10 @@ class VisitWebpageTool(Tool):
             from requests.exceptions import RequestException
 
             from smolagents.utils import truncate_content
-        except ImportError:
+        except ImportError as e:
             raise ImportError(
                 "You must install packages `markdownify` and `requests` to run this tool: for instance run `pip install markdownify requests`."
-            )
+            ) from e
         try:
             # Send a GET request to the URL
             response = requests.get(url)
@@ -286,9 +247,6 @@ class SpeechToTextTool(PipelineTool):
     default_checkpoint = "openai/whisper-large-v3-turbo"
     description = "This is a tool that transcribes an audio into text. It returns the transcribed text."
     name = "transcriber"
-    pre_processor_class = WhisperProcessor
-    model_class = WhisperForConditionalGeneration
-
     inputs = {
         "audio": {
             "type": "audio",
@@ -297,6 +255,18 @@ class SpeechToTextTool(PipelineTool):
     }
     output_type = "string"
 
+    def __new__(cls):
+        from transformers.models.whisper import (
+            WhisperForConditionalGeneration,
+            WhisperProcessor,
+        )
+
+        if not hasattr(cls, "pre_processor_class"):
+            cls.pre_processor_class = WhisperProcessor
+        if not hasattr(cls, "model_class"):
+            cls.model_class = WhisperForConditionalGeneration
+        return super().__new__()
+
     def encode(self, audio):
         audio = AgentAudio(audio).to_raw()
         return self.pre_processor(audio, return_tensors="pt")

src/smolagents/gradio_ui.py

@@ -19,14 +19,15 @@ import re
 import shutil
 from typing import Optional
 
-import gradio as gr
-
 from .agents import ActionStep, AgentStepLog, MultiStepAgent
 from .types import AgentAudio, AgentImage, AgentText, handle_agent_output_types
+from .utils import _is_package_available
 
 
 def pull_messages_from_step(step_log: AgentStepLog):
     """Extract ChatMessage objects from agent steps"""
+    import gradio as gr
+
     if isinstance(step_log, ActionStep):
         yield gr.ChatMessage(role="assistant", content=step_log.llm_output or "")
         if step_log.tool_calls is not None:
@@ -57,6 +58,11 @@ def stream_to_gradio(
     additional_args: Optional[dict] = None,
 ):
     """Runs an agent with the given task and streams the messages from the agent as gradio ChatMessages."""
+    if not _is_package_available("gradio"):
+        raise ModuleNotFoundError(
+            "Please install 'gradio' extra to use the GradioUI: `pip install 'smolagents[audio]'`"
+        )
+    import gradio as gr
 
     for step_log in agent.run(task, stream=True, reset=reset_agent_memory, additional_args=additional_args):
         for message in pull_messages_from_step(step_log):
@@ -88,6 +94,10 @@ class GradioUI:
     """A one-line interface to launch your agent in Gradio"""
 
     def __init__(self, agent: MultiStepAgent, file_upload_folder: str | None = None):
+        if not _is_package_available("gradio"):
+            raise ModuleNotFoundError(
+                "Please install 'gradio' extra to use the GradioUI: `pip install 'smolagents[audio]'`"
+            )
         self.agent = agent
         self.file_upload_folder = file_upload_folder
         if self.file_upload_folder is not None:
@@ -95,6 +105,8 @@ class GradioUI:
                 os.mkdir(file_upload_folder)
 
     def interact_with_agent(self, prompt, messages):
+        import gradio as gr
+
         messages.append(gr.ChatMessage(role="user", content=prompt))
         yield messages
         for msg in stream_to_gradio(self.agent, task=prompt, reset_agent_memory=False):
@@ -115,6 +127,7 @@ class GradioUI:
         """
         Handle file uploads, default allowed types are .pdf, .docx, and .txt
         """
+        import gradio as gr
 
         if file is None:
             return gr.Textbox("No file uploaded", visible=True), file_uploads_log
@@ -161,6 +174,8 @@ class GradioUI:
         )
 
     def launch(self):
+        import gradio as gr
+
         with gr.Blocks() as demo:
             stored_messages = gr.State([])
             file_uploads_log = gr.State([])

src/smolagents/models.py

@@ -21,20 +21,18 @@ import random
 from copy import deepcopy
 from dataclasses import asdict, dataclass
 from enum import Enum
-from typing import Any, Dict, List, Optional, Union
+from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union
 
 from huggingface_hub import InferenceClient
-from transformers import (
+from huggingface_hub.utils import is_torch_available
-    AutoModelForCausalLM,
-    AutoTokenizer,
-    StoppingCriteria,
-    StoppingCriteriaList,
-    is_torch_available,
-)
 
 from .tools import Tool
+from .utils import _is_package_available
 
 
+if TYPE_CHECKING:
+    from transformers import StoppingCriteriaList
+
 logger = logging.getLogger(__name__)
 
 DEFAULT_JSONAGENT_REGEX_GRAMMAR = {
@@ -320,6 +318,9 @@ class TransformersModel(Model):
 
     This model allows you to communicate with Hugging Face's models using the Inference API. It can be used in both serverless mode or with a dedicated endpoint, supporting features like stop sequences and grammar customization.
 
+    > [!TIP]
+    > You must have `transformers` and `torch` installed on your machine. Please run `pip install smolagents[transformers]` if it's not the case.
+
     Parameters:
         model_id (`str`, *optional*, defaults to `"Qwen/Qwen2.5-Coder-32B-Instruct"`):
             The Hugging Face model ID to be used for inference. This can be a path or model identifier from the Hugging Face model hub.
@@ -358,9 +359,12 @@ class TransformersModel(Model):
         **kwargs,
     ):
         super().__init__()
-        if not is_torch_available():
+        if not is_torch_available() or not _is_package_available("transformers"):
-            raise ImportError("Please install torch in order to use TransformersModel.")
+            raise ModuleNotFoundError(
+                "Please install 'transformers' extra to use 'TransformersModel': `pip install 'smolagents[transformers]'`"
+            )
         import torch
+        from transformers import AutoModelForCausalLM, AutoTokenizer
 
         default_model_id = "HuggingFaceTB/SmolLM2-1.7B-Instruct"
         if model_id is None:
@@ -387,7 +391,9 @@ class TransformersModel(Model):
             self.tokenizer = AutoTokenizer.from_pretrained(default_model_id)
             self.model = AutoModelForCausalLM.from_pretrained(model_id, device_map=device_map, torch_dtype=torch_dtype)
 
-    def make_stopping_criteria(self, stop_sequences: List[str]) -> StoppingCriteriaList:
+    def make_stopping_criteria(self, stop_sequences: List[str]) -> "StoppingCriteriaList":
+        from transformers import StoppingCriteria, StoppingCriteriaList
+
         class StopOnStrings(StoppingCriteria):
             def __init__(self, stop_strings: List[str], tokenizer):
                 self.stop_strings = stop_strings
@@ -491,6 +497,7 @@ class LiteLLMModel(Model):
             raise ModuleNotFoundError(
                 "Please install 'litellm' extra to use LiteLLMModel: `pip install 'smolagents[litellm]'`"
             )
+
         super().__init__()
         self.model_id = model_id
         # IMPORTANT - Set this to TRUE to add the function to the prompt for Non OpenAI LLMs
@@ -506,9 +513,10 @@ class LiteLLMModel(Model):
         grammar: Optional[str] = None,
         tools_to_call_from: Optional[List[Tool]] = None,
     ) -> ChatMessage:
-        messages = get_clean_message_list(messages, role_conversions=tool_role_conversions)
         import litellm
 
+        messages = get_clean_message_list(messages, role_conversions=tool_role_conversions)
+
         if tools_to_call_from:
             response = litellm.completion(
                 model=self.model_id,

src/smolagents/tools.py

@@ -35,54 +35,22 @@ from huggingface_hub import (
     metadata_update,
     upload_folder,
 )
-from huggingface_hub.utils import RepositoryNotFoundError
+from huggingface_hub.utils import is_torch_available
 from packaging import version
-from transformers.dynamic_module_utils import get_imports
-from transformers.utils import (
-    TypeHintParsingException,
-    cached_file,
-    get_json_schema,
-    is_accelerate_available,
-    is_torch_available,
-)
-from transformers.utils.chat_template_utils import _parse_type_hint
 
+from ._transformers_utils import (
+    TypeHintParsingException,
+    _parse_type_hint,
+    get_imports,
+    get_json_schema,
+)
 from .tool_validation import MethodChecker, validate_tool_attributes
-from .types import ImageType, handle_agent_input_types, handle_agent_output_types
+from .types import handle_agent_input_types, handle_agent_output_types
-from .utils import instance_to_source
+from .utils import _is_package_available, _is_pillow_available, instance_to_source
 
 
 logger = logging.getLogger(__name__)
 
-if is_accelerate_available():
-    from accelerate import PartialState
-    from accelerate.utils import send_to_device
-
-if is_torch_available():
-    from transformers import AutoProcessor
-else:
-    AutoProcessor = object
-
-TOOL_CONFIG_FILE = "tool_config.json"
-
-
-def get_repo_type(repo_id, repo_type=None, **hub_kwargs):
-    if repo_type is not None:
-        return repo_type
-    try:
-        hf_hub_download(repo_id, TOOL_CONFIG_FILE, repo_type="space", **hub_kwargs)
-        return "space"
-    except RepositoryNotFoundError:
-        try:
-            hf_hub_download(repo_id, TOOL_CONFIG_FILE, repo_type="model", **hub_kwargs)
-            return "model"
-        except RepositoryNotFoundError:
-            raise EnvironmentError(f"`{repo_id}` does not seem to be a valid repo identifier on the Hub.")
-        except Exception:
-            return "model"
-    except Exception:
-        return "space"
-
 
 def validate_after_init(cls):
     original_init = cls.__init__
@@ -337,12 +305,8 @@ class Tool:
             )
 
         # Save requirements file
+        imports = {el for el in get_imports(tool_file) if el not in sys.stdlib_module_names} | {"smolagents"}
         requirements_file = os.path.join(output_dir, "requirements.txt")
-
-        imports = []
-        for module in [tool_file]:
-            imports.extend(get_imports(module))
-        imports = list(set([el for el in imports + ["smolagents"] if el not in sys.stdlib_module_names]))
         with open(requirements_file, "w", encoding="utf-8") as f:
             f.write("\n".join(imports) + "\n")
 
@@ -439,53 +403,27 @@ class Tool:
                 `cache_dir`, `revision`, `subfolder`) will be used when downloading the files for your tool, and the
                 others will be passed along to its init.
         """
-        assert trust_remote_code, (
+        if not trust_remote_code:
+            raise ValueError(
                 "Loading a tool from Hub requires to trust remote code. Make sure you've inspected the repo and pass `trust_remote_code=True` to load the tool."
             )
 
-        hub_kwargs_names = [
-            "cache_dir",
-            "force_download",
-            "resume_download",
-            "proxies",
-            "revision",
-            "repo_type",
-            "subfolder",
-            "local_files_only",
-        ]
-        hub_kwargs = {k: v for k, v in kwargs.items() if k in hub_kwargs_names}
-
-        tool_file = "tool.py"
-
         # Get the tool's tool.py file.
-        hub_kwargs["repo_type"] = get_repo_type(repo_id, **hub_kwargs)
+        tool_file = hf_hub_download(
-        resolved_tool_file = cached_file(
             repo_id,
-            tool_file,
+            "tool.py",
             token=token,
-            **hub_kwargs,
+            repo_type="space",
-            _raise_exceptions_for_gated_repo=False,
+            cache_dir=kwargs.get("cache_dir"),
-            _raise_exceptions_for_missing_entries=False,
+            force_download=kwargs.get("force_download"),
-            _raise_exceptions_for_connection_errors=False,
+            resume_download=kwargs.get("resume_download"),
-        )
+            proxies=kwargs.get("proxies"),
-        tool_code = resolved_tool_file is not None
+            revision=kwargs.get("revision"),
-        if resolved_tool_file is None:
+            subfolder=kwargs.get("subfolder"),
-            resolved_tool_file = cached_file(
+            local_files_only=kwargs.get("local_files_only"),
-                repo_id,
-                tool_file,
-                token=token,
-                **hub_kwargs,
-                _raise_exceptions_for_gated_repo=False,
-                _raise_exceptions_for_missing_entries=False,
-                _raise_exceptions_for_connection_errors=False,
-            )
-        if resolved_tool_file is None:
-            raise EnvironmentError(
-                f"{repo_id} does not appear to provide a valid configuration in `tool_config.json` or `config.json`."
         )
 
-        with open(resolved_tool_file, encoding="utf-8") as reader:
+        tool_code = Path(tool_file).read_text()
-            tool_code = "".join(reader.readlines())
 
         # Find the Tool subclass in the namespace
         with tempfile.TemporaryDirectory() as temp_dir:
@@ -613,7 +551,10 @@ class Tool:
             def sanitize_argument_for_prediction(self, arg):
                 from gradio_client.utils import is_http_url_like
 
-                if isinstance(arg, ImageType):
+                if _is_pillow_available():
+                    from PIL.Image import Image
+
+                if _is_pillow_available() and isinstance(arg, Image):
                     temp_file = tempfile.NamedTemporaryFile(suffix=".png", delete=False)
                     arg.save(temp_file.name)
                     arg = temp_file.name
@@ -988,13 +929,13 @@ class PipelineTool(Tool):
 
     - **model_class** (`type`) -- The class to use to load the model in this tool.
     - **default_checkpoint** (`str`) -- The default checkpoint that should be used when the user doesn't specify one.
-    - **pre_processor_class** (`type`, *optional*, defaults to [`AutoProcessor`]) -- The class to use to load the
+    - **pre_processor_class** (`type`, *optional*, defaults to [`transformers.AutoProcessor`]) -- The class to use to load the
       pre-processor
-    - **post_processor_class** (`type`, *optional*, defaults to [`AutoProcessor`]) -- The class to use to load the
+    - **post_processor_class** (`type`, *optional*, defaults to [`transformers.AutoProcessor`]) -- The class to use to load the
       post-processor (when different from the pre-processor).
 
     Args:
-        model (`str` or [`PreTrainedModel`], *optional*):
+        model (`str` or [`transformers.PreTrainedModel`], *optional*):
             The name of the checkpoint to use for the model, or the instantiated model. If unset, will default to the
             value of the class attribute `default_checkpoint`.
         pre_processor (`str` or `Any`, *optional*):
@@ -1019,9 +960,9 @@ class PipelineTool(Tool):
             Any additional keyword argument to send to the methods that will load the data from the Hub.
     """
 
-    pre_processor_class = AutoProcessor
+    pre_processor_class = None
     model_class = None
-    post_processor_class = AutoProcessor
+    post_processor_class = None
     default_checkpoint = None
     description = "This is a pipeline tool"
     name = "pipeline"
@@ -1040,11 +981,10 @@ class PipelineTool(Tool):
         token=None,
         **hub_kwargs,
     ):
-        if not is_torch_available():
+        if not is_torch_available() or not _is_package_available("accelerate"):
-            raise ImportError("Please install torch in order to use this tool.")
+            raise ModuleNotFoundError(
-
+                "Please install 'transformers' extra to use a PipelineTool: `pip install 'smolagents[transformers]'`"
-        if not is_accelerate_available():
+            )
-            raise ImportError("Please install accelerate in order to use this tool.")
 
         if model is None:
             if self.default_checkpoint is None:
@@ -1071,6 +1011,10 @@ class PipelineTool(Tool):
         Instantiates the `pre_processor`, `model` and `post_processor` if necessary.
         """
         if isinstance(self.pre_processor, str):
+            if self.pre_processor_class is None:
+                from transformers import AutoProcessor
+
+                self.pre_processor_class = AutoProcessor
             self.pre_processor = self.pre_processor_class.from_pretrained(self.pre_processor, **self.hub_kwargs)
 
         if isinstance(self.model, str):
@@ -1079,12 +1023,18 @@ class PipelineTool(Tool):
         if self.post_processor is None:
             self.post_processor = self.pre_processor
         elif isinstance(self.post_processor, str):
+            if self.post_processor_class is None:
+                from transformers import AutoProcessor
+
+                self.post_processor_class = AutoProcessor
             self.post_processor = self.post_processor_class.from_pretrained(self.post_processor, **self.hub_kwargs)
 
         if self.device is None:
             if self.device_map is not None:
                 self.device = list(self.model.hf_device_map.values())[0]
             else:
+                from accelerate import PartialState
+
                 self.device = PartialState().default_device
 
         if self.device_map is None:
@@ -1115,6 +1065,7 @@ class PipelineTool(Tool):
 
     def __call__(self, *args, **kwargs):
         import torch
+        from accelerate.utils import send_to_device
 
         args, kwargs = handle_agent_input_types(*args, **kwargs)
 

src/smolagents/types.py

@@ -12,7 +12,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import importlib.util
 import logging
 import os
 import pathlib
@@ -22,26 +21,15 @@ from io import BytesIO
 
 import numpy as np
 import requests
-from transformers.utils import (
+from huggingface_hub.utils import is_torch_available
-    is_torch_available,
+from PIL import Image
-    is_vision_available,
+from PIL.Image import Image as ImageType
-)
+
+from .utils import _is_package_available
 
 
 logger = logging.getLogger(__name__)
 
-if is_vision_available():
-    from PIL import Image
-    from PIL.Image import Image as ImageType
-else:
-    ImageType = object
-
-if is_torch_available():
-    import torch
-    from torch import Tensor
-else:
-    Tensor = object
-
 
 class AgentType:
     """
@@ -94,9 +82,6 @@ class AgentImage(AgentType, ImageType):
         AgentType.__init__(self, value)
         ImageType.__init__(self)
 
-        if not is_vision_available():
-            raise ImportError("PIL must be installed in order to handle images.")
-
         self._path = None
         self._raw = None
         self._tensor = None
@@ -109,11 +94,15 @@ class AgentImage(AgentType, ImageType):
             self._raw = Image.open(BytesIO(value))
         elif isinstance(value, (str, pathlib.Path)):
             self._path = value
-        elif isinstance(value, torch.Tensor):
+        elif is_torch_available():
+            import torch
+
+            if isinstance(value, torch.Tensor):
                 self._tensor = value
-        elif isinstance(value, np.ndarray):
+            if isinstance(value, np.ndarray):
                 self._tensor = torch.from_numpy(value)
-        else:
+
+        if self._path is None and self._raw is None and self._tensor is None:
             raise TypeError(f"Unsupported type for {self.__class__.__name__}: {type(value)}")
 
     def _ipython_display_(self, include=None, exclude=None):
@@ -183,10 +172,12 @@ class AgentAudio(AgentType, str):
     """
 
     def __init__(self, value, samplerate=16_000):
-        if importlib.util.find_spec("soundfile") is None:
+        if not _is_package_available("soundfile") or not is_torch_available:
             raise ModuleNotFoundError(
                 "Please install 'audio' extra to use AgentAudio: `pip install 'smolagents[audio]'`"
             )
+        import torch
+
         super().__init__(value)
 
         self._path = None
@@ -223,6 +214,8 @@ class AgentAudio(AgentType, str):
         if self._tensor is not None:
             return self._tensor
 
+        import torch
+
         if self._path is not None:
             if "://" in str(self._path):
                 response = requests.get(self._path)
@@ -250,15 +243,7 @@ class AgentAudio(AgentType, str):
             return self._path
 
 
-AGENT_TYPE_MAPPING = {"string": AgentText, "image": AgentImage, "audio": AgentAudio}
+_AGENT_TYPE_MAPPING = {"string": AgentText, "image": AgentImage, "audio": AgentAudio}
-INSTANCE_TYPE_MAPPING = {
-    str: AgentText,
-    ImageType: AgentImage,
-    Tensor: AgentAudio,
-}
-
-if is_torch_available():
-    INSTANCE_TYPE_MAPPING[Tensor] = AgentAudio
 
 
 def handle_agent_input_types(*args, **kwargs):
@@ -268,16 +253,21 @@ def handle_agent_input_types(*args, **kwargs):
 
 
 def handle_agent_output_types(output, output_type=None):
-    if output_type in AGENT_TYPE_MAPPING:
+    if output_type in _AGENT_TYPE_MAPPING:
         # If the class has defined outputs, we can map directly according to the class definition
-        decoded_outputs = AGENT_TYPE_MAPPING[output_type](output)
+        decoded_outputs = _AGENT_TYPE_MAPPING[output_type](output)
         return decoded_outputs
-    else:
+
     # If the class does not have defined output, then we map according to the type
-        for _k, _v in INSTANCE_TYPE_MAPPING.items():
+    if isinstance(output, str):
-            if isinstance(output, _k):
+        return AgentText(output)
-                if _k is not object:  # avoid converting to audio if torch is not installed
+    if isinstance(output, ImageType):
-                    return _v(output)
+        return AgentImage(output)
+    if is_torch_available():
+        import torch
+
+        if isinstance(output, torch.Tensor):
+            return AgentAudio(output)
     return output
 
 

src/smolagents/utils.py

@@ -15,18 +15,30 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import ast
+import importlib.metadata
 import importlib.util
 import inspect
 import json
 import re
 import types
+from functools import lru_cache
 from typing import Dict, Tuple, Union
 
 from rich.console import Console
 
 
-def is_pygments_available():
+@lru_cache
-    return importlib.util.find_spec("soundfile") is not None
+def _is_package_available(package_name: str) -> bool:
+    try:
+        importlib.metadata.version(package_name)
+        return True
+    except importlib.metadata.PackageNotFoundError:
+        return False
+
+
+@lru_cache
+def _is_pillow_available():
+    return importlib.util.find_spec("PIL") is not None
 
 
 console = Console()

tests/test_default_tools.py

@@ -17,7 +17,7 @@ import unittest
 import pytest
 
 from smolagents.default_tools import PythonInterpreterTool, VisitWebpageTool
-from smolagents.types import AGENT_TYPE_MAPPING
+from smolagents.types import _AGENT_TYPE_MAPPING
 
 from .test_tools import ToolTesterMixin
 
@@ -46,7 +46,7 @@ class PythonInterpreterToolTester(unittest.TestCase, ToolTesterMixin):
     def test_agent_type_output(self):
         inputs = ["2 * 2"]
         output = self.tool(*inputs, sanitize_inputs_outputs=True)
-        output_type = AGENT_TYPE_MAPPING[self.tool.output_type]
+        output_type = _AGENT_TYPE_MAPPING[self.tool.output_type]
         self.assertTrue(isinstance(output, output_type))
 
     def test_agent_types_inputs(self):
@@ -56,13 +56,13 @@ class PythonInterpreterToolTester(unittest.TestCase, ToolTesterMixin):
         for _input, expected_input in zip(inputs, self.tool.inputs.values()):
             input_type = expected_input["type"]
             if isinstance(input_type, list):
-                _inputs.append([AGENT_TYPE_MAPPING[_input_type](_input) for _input_type in input_type])
+                _inputs.append([_AGENT_TYPE_MAPPING[_input_type](_input) for _input_type in input_type])
             else:
-                _inputs.append(AGENT_TYPE_MAPPING[input_type](_input))
+                _inputs.append(_AGENT_TYPE_MAPPING[input_type](_input))
 
         # Should not raise an error
         output = self.tool(*inputs, sanitize_inputs_outputs=True)
-        output_type = AGENT_TYPE_MAPPING[self.tool.output_type]
+        output_type = _AGENT_TYPE_MAPPING[self.tool.output_type]
         self.assertTrue(isinstance(output, output_type))
 
     def test_imports_work(self):

tests/test_final_answer.py

@@ -22,7 +22,7 @@ from transformers import is_torch_available
 from transformers.testing_utils import get_tests_dir, require_torch
 
 from smolagents.default_tools import FinalAnswerTool
-from smolagents.types import AGENT_TYPE_MAPPING
+from smolagents.types import _AGENT_TYPE_MAPPING
 
 from .test_tools import ToolTesterMixin
 
@@ -55,5 +55,5 @@ class FinalAnswerToolTester(unittest.TestCase, ToolTesterMixin):
         inputs = self.create_inputs()
         for input_type, input in inputs.items():
             output = self.tool(**input, sanitize_inputs_outputs=True)
-            agent_type = AGENT_TYPE_MAPPING[input_type]
+            agent_type = _AGENT_TYPE_MAPPING[input_type]
             self.assertTrue(isinstance(output, agent_type))

tests/test_tools.py

@@ -21,16 +21,12 @@ from unittest.mock import MagicMock, patch
 import mcp
 import numpy as np
 import pytest
+import torch
 from transformers import is_torch_available, is_vision_available
 from transformers.testing_utils import get_tests_dir
 
 from smolagents.tools import AUTHORIZED_TYPES, Tool, ToolCollection, tool
-from smolagents.types import (
+from smolagents.types import _AGENT_TYPE_MAPPING, AgentAudio, AgentImage, AgentText
-    AGENT_TYPE_MAPPING,
-    AgentAudio,
-    AgentImage,
-    AgentText,
-)
 
 
 if is_torch_available():
@@ -96,7 +92,7 @@ class ToolTesterMixin:
         inputs = create_inputs(self.tool.inputs)
         output = self.tool(**inputs, sanitize_inputs_outputs=True)
         if self.tool.output_type != "any":
-            agent_type = AGENT_TYPE_MAPPING[self.tool.output_type]
+            agent_type = _AGENT_TYPE_MAPPING[self.tool.output_type]
             self.assertTrue(isinstance(output, agent_type))
 
 

tests/test_types.py

@@ -121,4 +121,3 @@ class AgentTextTests(unittest.TestCase):
 
         self.assertEqual(string, agent_type.to_string())
         self.assertEqual(string, agent_type.to_raw())
-        self.assertEqual(string, agent_type)