This module provides a ValidationNode class that can be used to validate tool calls in a langchain graph. It applies a pydantic schema to tool_calls in the models' outputs, and returns a ToolMessage with the validated content. If the schema is not valid, it returns a ToolMessage with the error message. The ValidationNode can be used in a StateGraph with a "messages" key. If multiple tool calls are requested, they will be run in parallel.
A node that validates all tools requests from the last AIMessage.
It can be used either in StateGraph with a 'messages' key.
This node does not actually run the tools, it only validates the tool calls, which is useful for extraction and other use cases where you need to generate structured output that conforms to a complex schema without losing the original messages and tool IDs (for use in multi-turn conversations).
