A server/api/profile.get.ts handler that worked fine on Monday starts returning a NUXT_E8012 error on Tuesday, and the only thing that changed is a teammate added one line — reading the signed-in user's session with a helper imported from nuxt/server . Nothing else moved — not the route, not the defineEventHandler at the top of the file, not the dependency versions in any way you'd notice without reading package.json closely. The error message is honest about what's wrong, but only if you already know server/ now has two event shapes floating around, and that this one new line just handed a helper the wrong one.

This article is written against Nuxt 4.6, verified at v4.6.2 (the current latest on npm as of this writing; nuxt/server itself shipped in 4.6.0 , released October 5, 2026, per the official GitHub release notes ).…