> ## Documentation Index
> Fetch the complete documentation index at: https://docs.niteshift.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Preview authentication

> How classic repositories seed the browser session for the agent and previews.

<Note>
  This page covers repositories on the [classic setup
  script](/environment-configuration/setup-script). Repositories with committed `.niteshift/`
  configuration declare auth in the service manifest: see [Browser
  authentication](/environment-configuration/browser-authentication).
</Note>

Configure how the agent's browser and your preview links authenticate at **Settings → Repositories →
\[repository] → Preview Authentication**. Four strategies:

* **No auth**: previews show the unauthenticated view. No credentials are stored or injected.
* **Use static cookies across all tasks**: record a session once (or paste cookies in by hand) and
  Niteshift injects them into every task's browser and preview links. Best for hosted auth providers
  (AuthKit, Clerk, Okta) and persistent backing services (Neon, Supabase).
* **Per-task login**: your setup script writes cookies to `/tmp/agent-browser-state.json`, and
  Niteshift syncs that file to the agent's browser on launch and to preview links so you see the
  same authenticated session the agent does. Best for per-task seeded users or short-lived sessions.
  Use **Edit with agent** to have the setup agent draft the seeding code for you.
* **Manual login (username & password)**: add [custom instructions](https://niteshift.dev/settings)
  with test credentials (e.g. `user@example.com` / `test123`) and the login flow. The agent drives
  the login itself each task, and you can also log in manually on previews.

## Recording a session

Select **Use static cookies across all tasks**, click **Save**, then click **Record session**. From
there the flow is the
[same as for `.niteshift/` repositories](/environment-configuration/browser-authentication#recording-a-session):
a short-lived task boots an environment and opens the browser at your app, you take over via
**Control Browser** and log in, and **Save** stores the encrypted session scoped to the repository
and your user.

## Debugging login issues

Login failures share the
[same causes and fixes](/environment-configuration/browser-authentication#debugging-login-issues) as
`.niteshift/` repositories. The cookie strategies (**Use static cookies across all tasks** and
**Per-task login**) plant cookies before loading your application, so hosted sign-in pages that
refuse to render in an iframe never trigger; with **No auth**, apps that redirect to a login on
mount will fail to load in the preview.