MCP server Blockend

Blockend

Blockend copies backend source files into your project. You choose a block, and the CLI writes its code into your repository. The code is yours: read it, change it, commit it, or remove it.

The CLI supports Express, Fastify, Next.js App Router, and Hono. The add command requires TypeScript.

Quick start

npx blockend-cli init
npx blockend-cli add request-validator

init creates blockend.json with your framework, blocks directory, package manager, and import style. add writes the selected block.

import express from "express";
import { z } from "zod";
import { expressValidator } from "@/blocks/request-validator/adapters/express";

const app = express();
app.use(express.json());

const validate = expressValidator({
  body: z.object({
    name: z.string().min(1),
    email: z.string().email()
  })
});

app.post("/users", validate, (req, res) => {
  const { body } = validate.validated(req);
  res.status(201).json({ user: body });
});

app.listen(3000);

If your blockend.json uses a different alias, import from that path instead. With no alias, use the relative path under paths.blocks.

Blocks

Block	What it does
rate-limiter	Fixed-window limits with memory and Redis stores.
error-handler	Classifies errors, hides internal details, and returns one response shape.
logger	Pino logger with request IDs and async context.
request-validator	Validates body, query, and params with Zod.
response-formatter	Success, error, and pagination envelopes.
env-config	Validates environment variables with Zod at startup.
health-check	Dependency checks with per-check timeouts and a JSON health report.
graceful-shutdown	Drains requests and closes resources in priority order.
idempotency	Deduplicates retries with an atomic store lock.
password-hash	Argon2id hashing with a server-side pepper and rehash detection.
token-service	JWT access tokens and rotating refresh tokens.

How it works

1. init detects your project and writes blockend.json.
2. add filters the registry by framework, asks for a variant, and checks dependencies.
3. The CLI copies source files into your blocks directory and rewrites imports.
4. The block is recorded in blockend.json so update can compare versions.

There is no Blockend runtime dependency. Installed blocks use normal packages such as zod, pino, or jose.

CLI

Command	Description
blockend init	Create blockend.json.
blockend add <block>	Write a block into the project.
blockend add	Choose a block interactively.
blockend add --multi	Choose several blocks.
blockend list	List blocks for your framework.
blockend detect	Report framework, language, package manager, and project settings.
blockend diff <block>	Preview files without writing.
blockend doctor	Check config and project health.
blockend update	Compare installed blocks with registry versions.
blockend update --apply	Apply selected updates.
blockend mcp	Start the MCP server.
blockend mcp init	Write MCP client config.

See the CLI reference for options.

MCP

Blockend includes an MCP server for Claude Code, Cursor, VS Code, Codex CLI, and Windsurf.

npx blockend-cli mcp init --client cursor

The server exposes block listing, project detection, diff preview, install, update, and doctor tools. Installs run with --yes, so preview with the diff tool before writing.

Local development

Prerequisites:

• Node.js 20 or newer
• pnpm

git clone https://github.com/codewithnuh/blockend.git
cd blockend
pnpm install
pnpm build
pnpm dev

Useful commands:

pnpm test
pnpm lint
pnpm typecheck
pnpm validate

Repository layout

blockend/
├── apps/
│   └── web/                  Documentation site
├── blocks/                   Block source code
│   ├── error-handler/
│   ├── env-config/
│   ├── graceful-shutdown/
│   ├── health-check/
│   ├── idempotency/
│   ├── logger/
│   ├── password-hash/
│   ├── rate-limiter/
│   ├── request-validator/
│   ├── response-formatter/
│   └── token-service/
├── packages/
│   └── cli/                  CLI that copies blocks into projects
├── registry/
│   ├── config.json           Registry format version
│   └── index.json            Generated block metadata and file mappings
├── scripts/
├── turbo.json
└── pnpm-workspace.yaml

Each block usually contains:

• block.json with metadata and file topology
• core/ or a core file with framework-agnostic logic
• adapters/ for Express, Fastify, and Hono
• variants/ for storage implementations
• tests next to the source

Each block's block.json maps its source files to the paths the CLI writes. The checked-in registry/index.json is generated from those declarations. Some blocks also provide framework-specific tests and SQL.

Contributing

Read CONTRIBUTING.md before adding a block. A block should solve a common backend problem, keep its core framework-independent, and include tests for each adapter it ships.

Docs

• Documentation
• CLI reference
• Block reference
• Changelog
• Security policy

License

MIT. See LICENSE.