@modelcontextprotocol/server-legacy

Deprecated — This package is a frozen copy of v1 code for migration purposes only. It will not receive new features and is planned for removal in v3.

Provides two pieces of v1 server functionality removed in v2:

• SSE Transport (./sse) — The SSEServerTransport class, replaced in v2 by NodeStreamableHTTPServerTransport (from @modelcontextprotocol/node) or WebStandardStreamableHTTPServerTransport (from @modelcontextprotocol/server)
• OAuth Authorization Server (./auth) — The mcpAuthRouter and related helpers, removed in v2 because MCP servers should use dedicated OAuth providers

Installation

npm install @modelcontextprotocol/server-legacy

Usage

SSE Transport (no Express dependency required)

import { SSEServerTransport } from '@modelcontextprotocol/server-legacy/sse';

OAuth Auth Router (requires Express)

import { mcpAuthRouter } from '@modelcontextprotocol/server-legacy/auth';

Everything (requires Express)

import { SSEServerTransport, mcpAuthRouter } from '@modelcontextprotocol/server-legacy';

Migration

• SSE → StreamableHTTP: Use NodeStreamableHTTPServerTransport from @modelcontextprotocol/node (Node.js) or WebStandardStreamableHTTPServerTransport from @modelcontextprotocol/server (Web Standard / Cloudflare Workers)
• Auth router → Dedicated IdP: Use a dedicated OAuth provider (Auth0, Keycloak, etc.) instead of the built-in OAuth Authorization Server

Source: packages/server-legacy/README.md