Tanstack start dev server fails to start when debugger attached in Webstorm

Which project does this relate to?

Start

Describe the bug

Current behavior

1. Run pnpm dev with WebStorm debugger attached
2. Console reports ready, but all HTTP requests return 503 "Node env runner worker is unavailable"
3. No errors, no crashes in the console but the web app does not load properly

Your Example Website or App

git clone https://github.com/lionelhorn/tanstack-start-webstorm-repro

Steps to Reproduce the Bug or Issue

git clone https://github.com/lionelhorn/tanstack-start-webstorm-repro
cd start-basic
pnpm install

1. Open in WebStorm
2. Create a run configuration for pnpm dev with debugger attached
3. Run with debugger → open http://localhost:3000 → 503 with "Node env runner worker is unavailable"
4. Run without debugger → pages load normally

Expected behavior

http://localhost:3000 to return code 200 with website loaded
Using vscode to attach a debugger to pnpm dev works as expected

Screenshots or Videos

No response

Platform

• WebStorm (2025.3.2 Build #WS-253.30387.83)
• Node.js v24.11.1 (Windows 11 Pro x86_64)
• Vite 7.3.1 (TanStack Start)

Additional context

No response

Start with the linked tanstack-start-webstorm-repro repository: run pnpm install and compare pnpm dev with and without a WebStorm debugger attached. Trace the dev-server entry point responsible for the “Node env runner worker is unavailable” response, then verify that the debugger-attached run serves http://localhost:3000 with HTTP 200 instead of 503.