langchain-middleware

To add human-in-the-loop approval, you implement middleware patterns that pause LangChain agent execution before dangerous tool calls, requiring human approval, editing, or rejection before proceeding. This intercepts the tool invocation and manages the interruption safely.

To resume a LangGraph agent after a human-in-the-loop interruption, you use command resumption with thread-safe state management. This requires configuring a LangGraph checkpointer and thread-based configuration to ensure reliable agent state persistence.

Yes, you can intercept LangChain tool calls to add custom logging or retry logic by implementing custom middleware hooks. This pattern allows you to inject execution logic directly into the agent's tool invocation workflow.

You need to configure LangGraph checkpointers and thread-based configuration to maintain agent state during a paused tool call. This setup ensures reliable state persistence across the human-in-the-loop review period.

You prevent an AI agent from executing unauthorized actions in production by using middleware to require human approval before sensitive operations. This stops the agent from completing tasks like sending unauthorized emails or deleting database records without review.