langchain-human-in-the-loop

To pause a LangChain agent for human approval, you configure an interrupt-on tool pattern that halts execution before selected tool calls. This human-in-the-loop mechanism waits for a human decision before allowing the action to proceed.

You resume a LangChain workflow after an interrupt by passing a structured Command object containing the human's decision. This Command-based resume restarts execution while maintaining consistent thread IDs across invocations.

Human-in-the-loop workflow automation in LangChain is used for pausing agent execution to collect approvals, edits, or rejections. It is essential for sensitive operations like data deletions, gating external API interactions, or managing complex multi-tool workflows.

Yes, you need a checkpointer to enable human-in-the-loop interrupts. The checkpointer handles state persistence, allowing the agent to pause execution and maintain its state while awaiting human review decisions.

Yes, you can edit or reject tool call parameters during a LangChain agent workflow. The interrupt mechanism allows reviewers to modify parameters or completely halt flows based on their feedback before the action proceeds.

LangChain human-in-the-loop supports async and streaming to handle long-running tasks. This allows the agent to await human decisions asynchronously without blocking execution resources.