Casys MCP Platform

Everything you need to build, compose, and deploy production MCP servers.

The official SDK gives you the protocol. Casys MCP Platform gives you the production stack: composable middleware, OAuth2 auth, concurrency control, observability, interactive UIs, and multi-server composition — all in TypeScript.

rate-limit → auth → custom middleware → scope-check → validation → backpressure → handler

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Packages

Package	Status	Description
@casys/mcp-server	Production	The framework. Middleware, auth, dual transport, observability.
@casys/mcp-compose	Experimental	Multi-server UI composition — sync and orchestrate MCP Apps into dashboards.
@casys/mcp-bridge	Experimental	Deliver MCP Apps UIs through Telegram Mini Apps, LINE LIFF, and other messaging platforms.

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Quick Start

# npm
npm install @casys/mcp-server

# Deno
deno add jsr:@casys/mcp-server

STDIO Server

import { McpApp } from "@casys/mcp-server";

const server = new McpApp({ name: "my-server", version: "1.0.0" });

server.registerTool(
  {
    name: "greet",
    description: "Greet a user",
    inputSchema: {
      type: "object",
      properties: { name: { type: "string" } },
      required: ["name"],
    },
  },
  ({ name }) => `Hello, ${name}!`,
);

await server.start();

HTTP Server with Auth

import { createAuth0AuthProvider, McpApp } from "@casys/mcp-server";

const server = new McpApp({
  name: "my-api",
  version: "1.0.0",
  maxConcurrent: 10,
  backpressureStrategy: "queue",
  validateSchema: true,
  rateLimit: { maxRequests: 100, windowMs: 60_000 },
  auth: {
    provider: createAuth0AuthProvider({
      domain: "my-tenant.auth0.com",
      audience: "https://my-mcp.example.com",
      resource: "https://my-mcp.example.com",
    }),
  },
});

await server.startHttp({ port: 3000 });

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Why Casys MCP Platform?

	Official SDK	@casys/mcp-server
MCP protocol compliance	Yes	Yes
Composable middleware	—	Onion model (like Hono/Koa)
OAuth2 / JWT auth	—	4 OIDC presets + YAML config
Concurrency control	—	3 backpressure strategies
Rate limiting	—	Sliding window, per-client
Schema validation	—	JSON Schema (ajv)
Streamable HTTP + SSE	Manual	Built-in session management
OpenTelemetry tracing	—	Automatic spans per tool call
Prometheus metrics	—	/metrics endpoint
MCP Apps (UI resources)	Manual	registerResource() + ui://
Multi-server composition	—	@casys/mcp-compose

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Platform Overview

@casys/mcp-server — The Framework

The core of the platform. Build MCP servers with the same developer experience as Hono or Koa — register tools, plug in middleware, start serving.

Highlights:

• Middleware pipeline — rate-limit, auth, validation, backpressure, all composable
• 4 OAuth2 presets — Google, Auth0, GitHub Actions, generic OIDC
• Dual transport — STDIO for local/CLI, HTTP (Streamable HTTP + SSE) for remote
• Observability — OpenTelemetry spans + Prometheus metrics out of the box
• MCP Apps — serve interactive UIs as MCP resources

Full documentation and API reference

@casys/mcp-compose — Multi-Server Composition

Experimental — API may change.

Orchestrate multiple MCP Apps UIs into composite dashboards. Define layouts, sync rules between panels, and let the composition engine handle the event routing.

Documentation

@casys/mcp-bridge — Messaging Platform Bridge

Experimental — API may change.

Deliver MCP Apps interactive UIs through messaging platforms. Currently supports Telegram Mini Apps and LINE LIFF with platform-specific authentication and lifecycle handling.

Documentation

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Development

Deno workspace — cross-package imports resolve automatically.

# Tests
cd packages/server && deno task test     # 270 tests
cd packages/compose && deno task test    # 219 tests
cd packages/bridge && deno task test     # 120 tests

License

MIT