Test and debug

Before you ship, you exercise the app without infrastructure and validate the structure with a tool. Three things make that possible: the mock backend, the simulated auth adapter and fayz doctor.

Mock mode runs everything without a database

A freshly created app is born with "backend": { "provider": "mock" }. That means in-memory sample data — the whole app works without Supabase, without .env, without a network. Every plugin (and every plugin of yours, via createSafeDataProvider) ships a mock provider, so you can develop and demo the full experience before connecting anything. Flipping the switch to real data means changing provider in the manifest — see Supabase.

Simulated auth

In the same spirit, createMockAuthAdapter from @fayz-ai/auth gives you a session signed in as a demo user, persisted in the browser — no login screen, no provider. On the manifest-first path, the auth adapter follows backend.provider: in mock, auth is simulated automatically. That way you can test screens that depend on "being signed in" without setting up real auth. The details are in Auth — overview.

fayz doctor: the safety net

doctor validates the app at rest — without starting anything. Run it after any change:

npx @fayz-ai/cli doctor

It checks three things:

• Manifest structure and architectural boundaries — manifestVersion, required fields and surface with scaffold. A structural problem makes doctor exit with an error (exit 1). Today doctor validates the shape of the manifest and the boundaries, not the values of enums like theme.brand or backend.provider — validation of those values is on the way (there's an SDK fix in PR).
• Architecture boundaries — direct provider SDK imports (provider-import), imports outside the supported surface (off-surface-import), off-surface dependencies. Reported as warnings (soft enforcement — they don't fail the build).
• Referenced plugins — every id in the manifest has to resolve to an installed @fayz-ai/plugin-* factory wired into the generated code, plus locale coverage.

Typical output for a healthy mock app:

⚠ manifest references plugin(s) [dashboard] — each id must resolve to an installed @fayz-ai/plugin-* factory wired in src/plugins.generated.ts or src/config/app.tsx

0 error(s), 1 warning(s)

Plan migrations without touching the database

To debug the data layer, db apply --dry-run prints the ordered plan with no network calls and without reading your PAT — always safe to run:

npx @fayz-ai/cli db apply --dry-run

It's how you check what would be applied (and in what order: spine → drizzle → seed → plugins → incubator) before applying for real.

Next: put the app live with Static deploy.