docs: add Google-style docstrings to tools and llms modules (zapier, … (#31957)

**Description:**
Added standardized Google-style docstrings to improve documentation
consistency across key modules.

Updated files:
- `tools/zapier/tool.py`
- `tools/jira/tool.py`
- `tools/json/tool.py`
- `llms/base.py`

These changes enhance readability and maintain consistency with
LangChain’s documentation style guide.

**Issue:**
Fixes #21983

**Dependencies:**
None

**Twitter handle :**
@Akshara_p_

Author: Akshara-P-Vijayan

libs/langchain/langchain/llms/base.py

@@ -1,9 +1,17 @@
-# Backwards compatibility.
+"""
+This module provides backward-compatible exports of core language model classes.
+
+These classes are re-exported for compatibility with older versions of LangChain
+and allow users to import language model interfaces from a stable path.
+
+Exports:
+    - LLM: Abstract base class for all LLMs
+    - BaseLLM: Deprecated or foundational class for legacy LLMs
+    - BaseLanguageModel: Base class for core language model implementations
+"""
+
 from langchain_core.language_models import BaseLanguageModel
-from langchain_core.language_models.llms import (
-    LLM,
-    BaseLLM,
-)
+from langchain_core.language_models.llms import LLM, BaseLLM
 
 __all__ = [
     "LLM",

libs/langchain/langchain/tools/jira/tool.py

@@ -1,3 +1,14 @@
+"""
+This module provides dynamic access to deprecated Jira tools.
+
+When attributes like `JiraAction` are accessed, they are redirected to their new
+locations in `langchain_community.tools`. This ensures backward compatibility
+while warning developers about deprecation.
+
+Attributes:
+    JiraAction (deprecated): Dynamically loaded from langchain_community.tools.
+"""
+
 from typing import TYPE_CHECKING, Any
 
 from langchain._api import create_importer
@@ -14,7 +25,15 @@
 
 
 def __getattr__(name: str) -> Any:
-    """Look up attributes dynamically."""
+    """
+    Dynamically retrieve attributes from the updated module path.
+
+    Args:
+        name (str): The name of the attribute to import.
+
+    Returns:
+        Any: The resolved attribute from the updated path.
+    """
     return _import_attribute(name)
 
 

libs/langchain/langchain/tools/json/tool.py

@@ -1,3 +1,14 @@
+"""
+This module provides dynamic access to deprecated JSON tools in LangChain.
+
+It ensures backward compatibility by forwarding references such as
+`JsonGetValueTool`, `JsonListKeysTool`, and `JsonSpec` to their updated
+locations within the `langchain_community.tools` namespace.
+
+This setup allows legacy code to continue working while guiding developers
+toward using the updated module paths.
+"""
+
 from typing import TYPE_CHECKING, Any
 
 from langchain._api import create_importer
@@ -19,7 +30,18 @@
 
 
 def __getattr__(name: str) -> Any:
-    """Look up attributes dynamically."""
+    """
+    Dynamically retrieve attributes from the updated module path.
+
+    This method is used to resolve deprecated attribute imports
+    at runtime and forward them to their new locations.
+
+    Args:
+        name (str): The name of the attribute to import.
+
+    Returns:
+        Any: The resolved attribute from the appropriate updated module.
+    """
     return _import_attribute(name)
 
 

libs/langchain/langchain/tools/zapier/tool.py

@@ -1,3 +1,14 @@
+"""
+This module provides dynamic access to deprecated Zapier tools in LangChain.
+
+It supports backward compatibility by forwarding references such as
+`ZapierNLAListActions` and `ZapierNLARunAction` to their updated locations
+in the `langchain_community.tools` package.
+
+Developers using older import paths will continue to function, while LangChain
+internally redirects access to the newer, supported module structure.
+"""
+
 from typing import TYPE_CHECKING, Any
 
 from langchain._api import create_importer
@@ -17,7 +28,18 @@
 
 
 def __getattr__(name: str) -> Any:
-    """Look up attributes dynamically."""
+    """
+    Dynamically retrieve attributes from the updated module path.
+
+    This method is used to resolve deprecated attribute imports
+    at runtime and forward them to their new locations.
+
+    Args:
+        name (str): The name of the attribute to import.
+
+    Returns:
+        Any: The resolved attribute from the appropriate updated module.
+    """
     return _import_attribute(name)