langchain-middleware

Automate LangChain agent workflows with human-in-the-loop approval and custom middleware.

1|Updated Apr 30, 2026
One-click install
npx skills add https://github.com/wpsadi/stock-agent --skill langchain-middleware-wpsadi
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: langchain-middleware
Source: https://github.com/wpsadi/stock-agent/tree/main/.agents/skills/langchain-middleware
Command: npx skills add https://github.com/wpsadi/stock-agent --skill langchain-middleware-wpsadi

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires langchain, and includes scripts (resource) and references (resource) components.

What problem does it solve?

This Skill addresses the challenges of complex workflows in LangChain agents, particularly when human intervention is needed for critical decisions or custom logic is required for tool calls.

Core Features & Use Cases

  • Human-in-the-Loop (HITL) for Critical Decisions: Pauses before executing high-risk tool calls, allowing human approval.
  • Custom Middleware for Tool Calls: Intercepts tool calls for error handling, logging, and retries.
  • Command Resume: Continues execution after human decisions, ensuring smooth workflow transitions.
  • Structured Output: Generates output in a structured format like Pydantic or Zod for easy data handling.
  • Use Case: Ideal for complex LangChain-based systems that need to integrate human decisions into automated workflows, such as automated code review with manual override for complex issues.

Quick Start

To utilize the langchain-middleware, set up an agent with HITL middleware that will pause before sending sensitive emails for approval, and resume execution after human approval is received.

Frequently Asked Questions about langchain-middleware

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I add human-in-the-loop approval to LangChain agent workflows?

Human-in-the-loop approval in LangChain agent workflows pauses execution before high-risk tool calls, allowing human decisions. The agent uses custom middleware to intercept calls and resumes execution via command resume after approval is received.

Can I intercept LangChain tool calls for error handling and retries?

Yes, intercepting LangChain tool calls is possible using custom middleware. This middleware handles errors, logging, and retries for tool calls, ensuring complex workflows execute reliably before returning structured output.

How do I get structured output from a LangChain agent using Pydantic?

Structured output from a LangChain agent is generated using formats like Pydantic or Zod. The middleware configures the agent to return data structured for easy handling, ensuring reliable parsing of automated workflow results.

Does the LangChain middleware require Python for runtime execution?

Yes, Python is required for runtime execution and middleware configuration. The middleware relies on the LangChain dependency to automate complex workflows, configure human-in-the-loop logic, and handle tool calls.

What is the best way to resume LangChain agent execution after a manual override?

Command resume is the best way to continue LangChain agent execution after manual override. It ensures smooth workflow transitions by resuming the automated process immediately after human-in-the-loop decisions are made.

When should I use custom middleware in LangChain automated code review systems?

Use custom middleware in LangChain automated code review when manual override is needed for complex issues. It integrates human decisions into automated workflows, pausing critical tool calls for approval before generating structured output.