Bug: `chrome-devtools-mcp` fails to connect to Chrome when run via Bun (`bunx`)

[RichardFevrier]

Hi 👋

I was trying to use chrome-devtools-mcp with VSCodium (Flatpak) on NixOS, but when running it via bunx instead of npx, Puppeteer silently fails to connect to Chrome.

The error is:

Error: Could not connect to Chrome. Check if Chrome is running.
    at ensureBrowserConnected (.../browser.js:101:19)

It fails in ~25ms, suggesting immediate rejection. Both --browser-url=http://127.0.0.1:9222 and --ws-endpoint=ws://127.0.0.1:9222/devtools/browser/<id> fail the same way.

Chrome's endpoint is reachable — curl http://127.0.0.1:9222/json/version and Bun's native fetch() both return valid JSON. The issue is specific to Puppeteer when running under Bun.

Switching from bunx to npx (Node.js v20) resolved the issue immediately.

System Info

• OS: NixOS (VSCodium as Flatpak)
• Chrome: Chromium Flatpak v146 with remote debugging on 127.0.0.1:9222
• chrome-devtools-mcp: v0.20.3
• Runtime: Bun via bunx

Thank you

[RichardFevrier]

Wrong repo sorry