v1 included express (and hono in recent version), forcing the dependency down to users. (express being >1MB along with middleware deps such as express-rate-limit etc.).

Achieving final & true implementation of #1299

This PR decouples @modelcontextprotocol/server from HTTP frameworks completely, and introduces two plugin packages @modelcontextprotocol/server-express and @modelcontextprotocol/server-hono.

The plugin packages are optional, and users could choose to use them or to map to the MCP SDK themselves and not using any of these plugins.

However, the @modelcontextprotocol/server is completely HTTP framework dependency-free.

Some additional changes:

• Renamed StreamableHTTPServerTransport to NodeStreamableHTTPServerTransport
• Added linting rule to avoid inline type imports (e.g. import { A, type B}). Prefer import type { B } and import { A } on separate lines.

Motivation and Context

v2

How Has This Been Tested?

Unit tests

Breaking Changes

v2

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context