ERP-lite MCP Server

An enterprise-ready Model Context Protocol (MCP) server that exposes ERP functionalities to AI agents. Built as a portfolio project to demonstrate AI/ML engineering maturity, this project features a realistic data schema, a genuinely enforced human-in-the-loop approval workflow for write actions, and a full compliance-style audit trail.

Overview

As enterprise AI adoption accelerates, providing LLMs with direct read/write access to ERPs is becoming essential. However, autonomous agents should not execute consequential operations (like creating purchase orders or altering system configurations) without human oversight.

This server demonstrates a robust “human-in-the-loop” pattern:

• The AI agent can query open sales orders, check inventory levels, and identify low-stock items using its read-only tools.
• When an agent decides to replenish stock, it can only propose a purchase requisition in a pending_approval state.
• The agent cannot approve its own requisition. When it creates the requisition, a secure approval_token is generated and saved to the database, but is never returned to the agent.
• A human administrator can view pending requisitions and their tokens via a dedicated, authenticated REST endpoint (GET /admin/pending-requisitions) that sits entirely outside the MCP tool surface — no agent can reach it.
• The human retrieves the token through that endpoint and supplies it back to approve the requisition, closing the loop with a real access-control check (constant-time token comparison), not just a naming convention.
• Every tool call — successful or failed — is written to an append-only audit log, with sensitive values like approval_token redacted before persistence.

Architecture

graph TD
    Client[Claude Desktop / Custom Client] -- "MCP (stdio or Streamable HTTP with Bearer Token)" --> FastMCP[FastMCP Server]
    FastMCP -- "SQLAlchemy" --> DB[(PostgreSQL Database)]
    DB --> Seed[Seed Data]
    Admin[Human Admin] -- "X-Admin-Key (REST, outside MCP surface)" --> FastMCP

Demo

https://github.com/user-attachments/assets/8584d882-ecb2-43f2-bd31-7a095bedd25c

Checking low-stock inventory → agent proposing a purchase requisition → retrieving the approval token via the admin endpoint → approving the requisition → resulting audit log entry.

Quick Start (Docker)

First, create your .env file and set secure keys for both the MCP transport and the Admin API:

cp .env.example .env
# Edit .env and set MCP_API_KEY and ADMIN_API_KEY to secure, independent values

Then start the containers:

docker compose up

This spins up: