A local build needs SESSION_SECRET, and the failure lies about why

[catomean]

CLAUDE.md tells you to run next build before declaring UI work done, and never said how to run it here.

A bare npm run build on this laptop dies with:

Failed to collect configuration for /api/auth/demo

That route queries prisma.user, so the obvious reading is "this machine has no aoz_wohnen database — builds are impossible here."

That reading is wrong. The real cause is further down the same log:

[cause]: Error: SESSION_SECRET environment variable must be set in production

SESSION_SECRET=local-build-only npm run build   # exit 0, 56 static pages

It was believed twice on 2026-09-01 — once confidently enough that I reported it to George as an environment limitation. The cost of the wrong belief is skipping the one gate npm run verify explicitly does not cover: a 'use client' below an import passes lint, typecheck and Jest, and fails only at build.

Two traps stacked underneath it

• Never pipe the build. npm run build | tail -25 exits with tail's status, so a failed build reports success. This bit twice in one session.
• An error naming a database-touching route is not evidence about the database. The first line says where it broke, not why. Read to [cause].

Docs only — no code change.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Cd183M6472xBgTKWA2is6h