ToolNode is a built-in LangGraph node for turning an assistant’s requested tool calls into actual tool results. It reads the latest message in graph state, executes matching tools, and appends each result as a ToolMessage. This lets a support assistant perform actions instead of only generating replies. section 10.6.4 section 10.7
A typical agent graph connects ToolNode to the assistant in a short tool-use loop:
- Route from the assistant to the tools node when the latest assistant message contains tool calls by using tools_condition. section 10.6.4
- Return from tools to the assistant so it can use the ToolMessage output to continue the interaction. section 10.6.4
A support assistant that acts
A support assistant can use ToolNode to handle real-world requests such as tracking or canceling orders. Internal tool messages can be filtered from the conversation shown to the user while remaining available in graph state.
