MERN MCP

AI-Powered MERN Stack CRUD Scaffolder and MCP Server

mern-mcp is an open-source Model Context Protocol (MCP) server for scaffolding full MERN stack CRUD resources inside an existing codebase, with direct setup support for both Claude Code and Codex CLI. It generates MongoDB and Mongoose models, Express services and routes, React client modules, and the wiring needed to plug new resources into a real application with a safer preview-before-apply workflow.

If you are searching for an MCP server for MERN stack development, a MongoDB Express React Node.js CRUD generator, a Mongoose plus Express boilerplate generator, or a React admin scaffolder that works with AI coding assistants, this repository is built for that exact use case.

Index: Why Useful · Generated Files · Install · Config · Claude Code · Codex CLI · Docker · MCP Tools · Example · Project Styles · Natural Language · Preview Workflow · Who It's For

Why This Repository Is Useful

Teams usually do not need another generic code generator. They need a local MCP tool that can inspect a project, follow an existing folder structure, create repeatable CRUD slices, and avoid blind writes. mern-mcp focuses on that practical workflow.

Even if you already have MCPs for Next.js, Node.js, or MongoDB, those tools usually help at the framework or database level. mern-mcp is useful because it handles the full resource workflow in one place: model, service, controller, routes, validators, client API, hooks, forms, list views, detail views, and integration patches. Instead of asking an assistant to wire each layer separately, a developer can scaffold an entire CRUD slice in one pass, review the plan, and move on to the business logic faster. That cuts repetitive setup work, reduces missed integration steps, and makes day-to-day full-stack development much less tedious.

It is especially useful when you want to:

• scaffold a MERN CRUD API and React UI from a resource schema
• generate Mongoose models, Express controllers, services, routes, and validators
• generate React forms, list views, detail views, hooks, shared types, and API modules
• let an MCP-compatible coding assistant create resources inside your own repo
• preview file changes before applying them
• manage generated resources over time with add-field and delete workflows
• support monorepo or separate server and client projects

What mern-mcp Generates

For each resource, mern-mcp can generate:

• server model file
• server service file
• server controller file
• server routes file
• server validator file when validation is enabled
• auth middleware file when JWT auth is enabled
• client shared types file
• client API module
• client data hook
• client form component
• client list component
• client detail component

Typical generated paths look like:

server/models/product.model.ts
server/services/product.service.ts
server/controllers/product.controller.ts
server/routes/product.routes.ts
server/validators/product.validator.ts
client/types/product.types.ts
client/api/product.api.ts
client/hooks/useProduct.ts
client/components/ProductForm.tsx
client/components/ProductList.tsx
client/components/ProductDetail.tsx

The planner can also patch existing files when it detects supported patterns:

• mount new Express routes in a server entry file
• register new routes in a React Router file
• register reducers in a Redux store when the detected store shape is supported

Installation

npm install
npm run build

Run the compiled MCP server against a target MERN project:

node dist/index.js --project-root /absolute/path/to/target-project

For local development:

npm run dev -- --project-root /absolute/path/to/target-project

Configuration

Create mern-mcp.config.json in the target project root.

Example for a monorepo TypeScript project using React Query:

{
  "structure": "monorepo",
  "language": "typescript",
  "reactStack": "react-query",
  "validation": "zod",
  "auth": "none",
  "rbac": false,
  "paths": {
    "serverRoot": "./server",
    "clientRoot": "./client",
    "serverEntry": "index.ts",
    "clientRouter": "router.tsx"
  }
}

Example for separate client and server apps with Redux and JWT auth:

{
  "structure": "separate",
  "language": "typescript",
  "reactStack": "redux",
  "validation": "both",
  "auth": "jwt",
  "paths": {
    "serverRoot": "./server",
    "clientRoot": "./client",
    "modelsDir": "src/models",
    "servicesDir": "src/services",
    "controllersDir": "src/controllers",
    "routesDir": "src/routes",
    "validatorsDir": "src/validators",
    "middlewareDir": "src/middleware",
    "componentsDir": "src/components",
    "hooksDir": "src/hooks",
    "apiDir": "src/api",
    "typesDir": "src/types",
    "serverEntry": "src/index.ts",
    "clientRouter": "src/router.tsx",
    "clientStore": "src/store.ts"
  }
}

All artifact directories are overridable through paths.

Use With Claude Code

1. Install dependencies and build this repository:

npm install
npm run build

2. Create mern-mcp.config.json in the target MERN project you want to scaffold.
3. Add the MCP server to Claude Code:

claude mcp add mern-mcp -- node /absolute/path/to/mern-mcp/dist/index.js --project-root /absolute/path/to/project

4. Confirm the server is available in Claude Code.
5. Start with preview_scaffold before using scaffold_resource in apply mode.

Use With Codex CLI

1. Install dependencies and build this repository:

npm install
npm run build

2. Create mern-mcp.config.json in the target MERN project you want to scaffold.
3. Add the MCP server to Codex CLI:

codex mcp add mern-mcp --command node --args /absolute/path/to/mern-mcp/dist/index.js --project-root /absolute/path/to/project

4. Confirm the MCP server is listed in Codex.
5. Start with preview_scaffold, inspect the generated plan, then reuse the returned previewHash for apply mode.

Run With Docker

You can run mern-mcp in Docker if you do not want to install Node.js directly on the host.

1. Build the image from this repository:

docker build -t mern-mcp .

2. Make sure the target MERN project contains mern-mcp.config.json.
3. Run the container and mount the target project into it:

docker run --rm -i \
  -v /absolute/path/to/target-project:/workspace \
  mern-mcp \
  --project-root /workspace

4. If you want to register the Dockerized server in an MCP client, use Docker as the command and pass the same arguments.

Example shape:

docker run --rm -i -v /absolute/path/to/target-project:/workspace mern-mcp --project-root /workspace

MCP Tools

The server currently registers these tools:

• preview_scaffold
• scaffold_resource
• list_resources
• add_field
• delete_resource

preview_scaffold

Dry-run a scaffold and inspect the generated write plan before changing files.

scaffold_resource

Preview or apply a full MERN CRUD scaffold for a resource.

list_resources

List manifest-managed resources and optionally scan for unmanaged resources in the project.

add_field

Preview or apply a new field on an existing generated resource.

delete_resource

Preview or apply deletion for a generated resource and remove its manifest record.

For scaffold_resource, add_field, and delete_resource, the important inputs are:

• mode: "preview" or "apply"
• previewHash: required in "apply" mode
• conflictStrategy: "abort", "overwrite", or "skip"

Example Resource Input

Example preview request for a product resource:

{
  "resourceName": "Product",
  "fields": [
    { "name": "title", "type": "string", "required": true },
    { "name": "price", "type": "number", "required": true },
    { "name": "inStock", "type": "boolean", "required": false }
  ],
  "mode": "preview"
}

After previewing, reuse the returned previewHash for apply mode.

Supported Project Styles

mern-mcp supports configurable MERN code generation across these dimensions:

• project structure: monorepo or separate
• language: typescript or javascript
• React data stack: plain, react-query, redux, or axios
• validation: zod, express-validator, both, or none
• auth: jwt or none