WebLLM Works in Dev But Fails on Vercel: The CSP Directive You're Missing

WebGPU was detected, the consent dialog appeared, the user granted consent, and the network tab showed a clean 200 OK on the WASM fetch. Then nothing. No console output, no progress events. The UI showed "Enhanced analysis unavailable. Try again." In npm run dev , against the same code on the same browser, everything worked. I almost spent an afternoon on the wrong theory. The reason I didn't is the reason for this post. When you're debugging, anomalies are easier to chase than absences. The 200