Add Hono utilities and example

[brettimus]

Overview

Adds a new folder hono/ with utilities and examples for building an authenticated (Hono-based) MCP server with Clerk.

At the moment, this PR focuses on Clerk utilities only, and does not export general-purpose helpers like the express/ module does.

Worth Noting

Web Standard api frameworks like Hono do not play nicely with the @modelcontextprotocol/sdk typescript package, since that package is rather Express-and-Node.js specific.

(This is why Hono has its own package for building MCP servers, which re-implements the StreamableHTTPTransport under the hood.)

Currently, the Hono mcp middleware does not have a way to pass auth down to tools (it's WIP), but this is something that the mcp-lite SDK does (disclosure: I am a maintainer), which is why I included it in an example.

Exports of @clerk/mcp-tools/hono

• mcpAuthClerk - Hono authentication middleware
• oauthCorsMiddleware - cors middleware for the oauth metadata handlers
• protectedResourceHandlerClerk - handler that returns metadata for the resource server (Hono app)
• authServerMetadataHandlerClerk - handler that returns Clerk auth server metadata

How I tested

I published this package under a different scope (@bretterplane/mcp-tools) and made sure the example from the Hono README worked in the repo here without import or type errors.

To configure Clerk, I created an application, then enabled OAuth + DCR.

To test the auth flow, I ran the @modelcontextprotocol/inspector and used the guided OAuth flow to check each step. (Discovery, client registration, etc.)

Finally, I used the inspector to execute the authenticated tool, and it worked (fetching auth'd user info from Clerk).

TODOs

• Add general purpose mcp auth utils? (Utilities that do not assume usage of Clerk)
• Update hono/README.md to fix get_clerk_user_data tool
• Update hono/README.md to document oauthCorsMiddleware
• Test the Hono utilities in the wild with a published package (I will do this)