🔴 Bug: `Redis error [Error: Socket closed unexpectedly]`

[pstaylor-patrick]

Links

• split from related bug at 🔴 Bug: Error: redisUrl is required #16
• duplicated to 🔴 Bug: Redis error [Error: Socket closed unexpectedly] vercel/mcp-handler#61 for discoverability

Dev Notes

• I suspect this is an issue in https://github.com/vercel/mcp-adapter, not https://github.com/vercel-labs/mcp-for-next.js

Steps to Reproduce

1. checkout my forked fix branch at Fix Error: redisUrl is required #17 (https://github.com/servant-io/mcp-for-next.js/tree/fix/redisUrl)
2. run:

   #/usr/bin/env bash
   nvm install
   nvm use
   pnpm install -D
   
   # https://github.com/redis/node-redis/blob/9ea260f/packages/client/lib/client/index.ts#L33
   # replace `redis[s]://[[username][:password]@][host][:port][/db-number]` with your actual `REDIS_URL`
   echo "REDIS_URL=\"redis[s]://[[username][:password]@][host][:port][/db-number]\"" > .env.local
   
   pnpm build
   pnpm dev

3. in another terminal, run:

   #/usr/bin/env bash
   nvm install
   nvm use
   
   # no need to globally install mcp sdk because I
   # rolled it into the dev dependencies
   # npm i -g @modelcontextprotocol/sdk@latest
   
   pnpm test:client http://localhost:3000

4. 🔴 see that the output reads:

   > next.js-mcp-server@0.1.0 dev /Users/patrick/src/servant-io/mcp-for-next.js
   > next dev
   
      ▲ Next.js 15.2.4
      - Local:        http://localhost:3000
      - Network:      http://192.168.1.52:3000
      - Environments: .env.local
   
    ✓ Starting...
    ✓ Ready in 1650ms
    ○ Compiling /[transport] ...
    ✓ Compiled /[transport] in 1458ms (999 modules)
   Redis error [Error: Socket closed unexpectedly]
   Redis error [Error: Socket closed unexpectedly]
   Redis error [Error: Socket closed unexpectedly]

[pstaylor-patrick]

🔵 started a work-in-progress (WIP) fix at vercel/mcp-handler#62

[quuu]

hey @pstaylor-patrick closing to track and discuss in: vercel/mcp-handler#61