core[minor], langchain[patch]: tools dependencies refactoring (#18759)

The `langchain.tools`
[namespace](https://api.python.langchain.com/en/latest/langchain_api_reference.html#module-langchain.tools)
can be completely eliminated by moving one class and 3 functions into
`core`. It makes sense since the class and functions are very core.

libs/core/langchain_core/tools.py

@@ -23,6 +23,7 @@ import inspect
 import uuid
 import warnings
 from abc import abstractmethod
+from functools import partial
 from inspect import signature
 from typing import Any, Awaitable, Callable, Dict, List, Optional, Tuple, Type, Union
 
@@ -32,9 +33,17 @@ from langchain_core.callbacks import (
     BaseCallbackManager,
     CallbackManager,
     CallbackManagerForToolRun,
+)
+from langchain_core.callbacks.manager import (
     Callbacks,
 )
 from langchain_core.load.serializable import Serializable
+from langchain_core.prompts import (
+    BasePromptTemplate,
+    PromptTemplate,
+    aformat_document,
+    format_document,
+)
 from langchain_core.pydantic_v1 import (
     BaseModel,
     Extra,
@@ -44,6 +53,7 @@ from langchain_core.pydantic_v1 import (
     root_validator,
     validate_arguments,
 )
+from langchain_core.retrievers import BaseRetriever
 from langchain_core.runnables import (
     Runnable,
     RunnableConfig,
@@ -920,3 +930,111 @@ def tool(
         return _partial
     else:
         raise ValueError("Too many arguments for tool decorator")
+
+
+class RetrieverInput(BaseModel):
+    """Input to the retriever."""
+
+    query: str = Field(description="query to look up in retriever")
+
+
+def _get_relevant_documents(
+    query: str,
+    retriever: BaseRetriever,
+    document_prompt: BasePromptTemplate,
+    document_separator: str,
+    callbacks: Callbacks = None,
+) -> str:
+    docs = retriever.get_relevant_documents(query, callbacks=callbacks)
+    return document_separator.join(
+        format_document(doc, document_prompt) for doc in docs
+    )
+
+
+async def _aget_relevant_documents(
+    query: str,
+    retriever: BaseRetriever,
+    document_prompt: BasePromptTemplate,
+    document_separator: str,
+    callbacks: Callbacks = None,
+) -> str:
+    docs = await retriever.aget_relevant_documents(query, callbacks=callbacks)
+    return document_separator.join(
+        [await aformat_document(doc, document_prompt) for doc in docs]
+    )
+
+
+def create_retriever_tool(
+    retriever: BaseRetriever,
+    name: str,
+    description: str,
+    *,
+    document_prompt: Optional[BasePromptTemplate] = None,
+    document_separator: str = "\n\n",
+) -> Tool:
+    """Create a tool to do retrieval of documents.
+
+    Args:
+        retriever: The retriever to use for the retrieval
+        name: The name for the tool. This will be passed to the language model,
+            so should be unique and somewhat descriptive.
+        description: The description for the tool. This will be passed to the language
+            model, so should be descriptive.
+
+    Returns:
+        Tool class to pass to an agent
+    """
+    document_prompt = document_prompt or PromptTemplate.from_template("{page_content}")
+    func = partial(
+        _get_relevant_documents,
+        retriever=retriever,
+        document_prompt=document_prompt,
+        document_separator=document_separator,
+    )
+    afunc = partial(
+        _aget_relevant_documents,
+        retriever=retriever,
+        document_prompt=document_prompt,
+        document_separator=document_separator,
+    )
+    return Tool(
+        name=name,
+        description=description,
+        func=func,
+        coroutine=afunc,
+        args_schema=RetrieverInput,
+    )
+
+
+ToolsRenderer = Callable[[List[BaseTool]], str]
+
+
+def render_text_description(tools: List[BaseTool]) -> str:
+    """Render the tool name and description in plain text.
+
+    Output will be in the format of:
+
+    .. code-block:: markdown
+
+        search: This tool is used for search
+        calculator: This tool is used for math
+    """
+    return "\n".join([f"{tool.name}: {tool.description}" for tool in tools])
+
+
+def render_text_description_and_args(tools: List[BaseTool]) -> str:
+    """Render the tool name, description, and args in plain text.
+
+    Output will be in the format of:
+
+    .. code-block:: markdown
+
+        search: This tool is used for search, args: {"query": {"type": "string"}}
+        calculator: This tool is used for math, \
+args: {"expression": {"type": "string"}}
+    """
+    tool_strings = []
+    for tool in tools:
+        args_schema = str(tool.args)
+        tool_strings.append(f"{tool.name}: {tool.description}, args: {args_schema}")
+    return "\n".join(tool_strings)

libs/langchain/langchain/tools/render.py

@@ -4,10 +4,13 @@ Depending on the LLM you are using and the prompting strategy you are using,
 you may want Tools to be rendered in a different way.
 This module contains various ways to render tools.
 """
-from typing import Callable, List
 
 # For backwards compatibility
-from langchain_core.tools import BaseTool
+from langchain_core.tools import (
+    ToolsRenderer,
+    render_text_description,
+    render_text_description_and_args,
+)
 from langchain_core.utils.function_calling import (
     format_tool_to_openai_function,
     format_tool_to_openai_tool,
@@ -20,37 +23,3 @@ __all__ = [
     "format_tool_to_openai_tool",
     "format_tool_to_openai_function",
 ]
-
-
-ToolsRenderer = Callable[[List[BaseTool]], str]
-
-
-def render_text_description(tools: List[BaseTool]) -> str:
-    """Render the tool name and description in plain text.
-
-    Output will be in the format of:
-
-    .. code-block:: markdown
-
-        search: This tool is used for search
-        calculator: This tool is used for math
-    """
-    return "\n".join([f"{tool.name}: {tool.description}" for tool in tools])
-
-
-def render_text_description_and_args(tools: List[BaseTool]) -> str:
-    """Render the tool name, description, and args in plain text.
-
-    Output will be in the format of:
-
-    .. code-block:: markdown
-
-        search: This tool is used for search, args: {"query": {"type": "string"}}
-        calculator: This tool is used for math, \
-args: {"expression": {"type": "string"}}
-    """
-    tool_strings = []
-    for tool in tools:
-        args_schema = str(tool.args)
-        tool_strings.append(f"{tool.name}: {tool.description}, args: {args_schema}")
-    return "\n".join(tool_strings)

libs/langchain/langchain/tools/retriever.py

@@ -1,90 +1,15 @@
-from functools import partial
-from typing import Optional
-
-from langchain_core.callbacks.manager import (
-    Callbacks,
+from langchain_core.tools import (
+    RetrieverInput,
+    ToolsRenderer,
+    create_retriever_tool,
+    render_text_description,
+    render_text_description_and_args,
 )
-from langchain_core.prompts import (
-    BasePromptTemplate,
-    PromptTemplate,
-    aformat_document,
-    format_document,
-)
-from langchain_core.pydantic_v1 import BaseModel, Field
-from langchain_core.retrievers import BaseRetriever
 
-from langchain.tools import Tool
-
-
-class RetrieverInput(BaseModel):
-    """Input to the retriever."""
-
-    query: str = Field(description="query to look up in retriever")
-
-
-def _get_relevant_documents(
-    query: str,
-    retriever: BaseRetriever,
-    document_prompt: BasePromptTemplate,
-    document_separator: str,
-    callbacks: Callbacks = None,
-) -> str:
-    docs = retriever.get_relevant_documents(query, callbacks=callbacks)
-    return document_separator.join(
-        format_document(doc, document_prompt) for doc in docs
-    )
-
-
-async def _aget_relevant_documents(
-    query: str,
-    retriever: BaseRetriever,
-    document_prompt: BasePromptTemplate,
-    document_separator: str,
-    callbacks: Callbacks = None,
-) -> str:
-    docs = await retriever.aget_relevant_documents(query, callbacks=callbacks)
-    return document_separator.join(
-        [await aformat_document(doc, document_prompt) for doc in docs]
-    )
-
-
-def create_retriever_tool(
-    retriever: BaseRetriever,
-    name: str,
-    description: str,
-    *,
-    document_prompt: Optional[BasePromptTemplate] = None,
-    document_separator: str = "\n\n",
-) -> Tool:
-    """Create a tool to do retrieval of documents.
-
-    Args:
-        retriever: The retriever to use for the retrieval
-        name: The name for the tool. This will be passed to the language model,
-            so should be unique and somewhat descriptive.
-        description: The description for the tool. This will be passed to the language
-            model, so should be descriptive.
-
-    Returns:
-        Tool class to pass to an agent
-    """
-    document_prompt = document_prompt or PromptTemplate.from_template("{page_content}")
-    func = partial(
-        _get_relevant_documents,
-        retriever=retriever,
-        document_prompt=document_prompt,
-        document_separator=document_separator,
-    )
-    afunc = partial(
-        _aget_relevant_documents,
-        retriever=retriever,
-        document_prompt=document_prompt,
-        document_separator=document_separator,
-    )
-    return Tool(
-        name=name,
-        description=description,
-        func=func,
-        coroutine=afunc,
-        args_schema=RetrieverInput,
-    )
+__all__ = [
+    "RetrieverInput",
+    "ToolsRenderer",
+    "create_retriever_tool",
+    "render_text_description",
+    "render_text_description_and_args",
+]