mcp-agent-langchainjs: Instructions file for Codex

AGENTS.md

mcp-agent-langchainjs AGENTS.md is an instructions file for Codex, OpenCode from Azure-Samples/mcp-agent-langchainjs. It costs 441 tokens per session, scanned A, original, MIT.

Project instructions for an Azure and LangChain.js demonstration app that uses AI agents to handle burger orders. The app is split into web, business, and Model Context Protocol services, where Model Context Protocol is a way for an AI agent to call external tools.

In plain words
What is it for?
Use it when working on the project’s architecture, authentication, saved conversations, TypeScript code, or communication between the agent, burger-ordering, and tool services.
Why use it?
It explains how the project’s parts communicate and how user sign-in and chat history are handled. This helps developers make changes without overlooking dependencies between services.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md.

This is Azure-Samples/mcp-agent-langchainjs's own configuration. It tells Codex and OpenCode how to work on mcp-agent-langchainjs itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mcp-agent-langchainjs configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Azure-Samples/mcp-agent-langchainjs. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Azure-Samples/mcp-agent-langchainjs/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/Azure-Samples/mcp-agent-langchainjs

Made for: Codex, OpenCode.

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Per session 441 This file is loaded in full into every session.
When invoked 441 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00441 $0.00441
Opus 5.5 $0.00176 $0.00176
Sonnet 5.5 $0.00088 $0.00088
Haiku 4.5 $0.00044 $0.00044

Measured 1mo ago against content hash d8141e881f18, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcp-agent-langchainjs AGENTS.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

AGENTS.md · 44 lines

How it starts

The opening of the file, as written. The whole thing — 44 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCP Agent LangChain.js Project Instructions

Architecture Overview

This is a multi-component LangChain.js demo showcasing AI agents with Model Context Protocol (MCP) integration. The system demonstrates a burger ordering platform with three main service layers:

  • Agent Layer: AI chat interface (agent-webapp + agent-api) using LangChain.js agents with MCP tools
  • Business Layer: Burger ordering API (burger-api) and webapp (burger-webapp)
  • MCP Layer: Model Context Protocol server (burger-mcp) exposing burger API as LLM tools

Component Communication Flow

agent-webapp → agent-api → burger-mcp → burger-api

The agent uses LangChain.js with Azure OpenAI, connects to the MCP server via StreamableHTTPClientTransport, and the MCP server proxies requests to the burger API.

Key Architectural Patterns

Authentication & State Management

  • Azure Static Web Apps authentication provides userId context
  • Cosmos DB for chat history storage using @langchain/azure-cosmosdb
  • User context flows: SWA auth → agent-api → MCP tools (for user-specific operations)

TypeScript & Build Conventions

  • Shared XO linting config with project-specific overrides
  • NPM workspace-based dependency management
  • .js extensions required in imports for ESM compatibility
  • Keep the code simple and straighforward: avoid unnecessary complexity and ensure clarity in implementation.
  • Do not use comments except where absolutely necessary, code should be self-explanatory.

Infrastructure as Code

  • Bicep templates in infra/ for Azure deployment
  • azure.yaml defines multi-service deployment strategy:
    • burger-api, agent-api: Azure Functions (Flex Consumption)
    • burger-mcp: Azure Functions (Flex Consumption)
    • *-webapp: Static Web Apps
  • Environment variables flow through Azure App Settings
  • @azure Rule - Use Azure Best Practices: When generating code for Azure, running terminal commands for Azure, or performing operations related to Azure, invoke your azure_development-get_best_practices tool if available.

Read the full file on GitHub · 44 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago First seen · 44 lines · 441 tokens per session scan A d8141e881f18

Subscribe to this mod's changes

mcp-agent-langchainjs AGENTS.md is an instructions file published in the GitHub repository Azure-Samples/mcp-agent-langchainjs (204 stars, last pushed 3mo ago), licensed MIT. It adds 441 tokens to every session, about $0.0018 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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