# VIEWER_SIGN_IN_REQUIRED

**What it means.** This app is private. Sign in with the email it was shared with to open it.

**What to do.** Sign in in the Uarpie viewer with the email address the owner invited, then open the app again.

- HTTP status: 401
- Retryable after applying the fix: yes

Every failure from the CLI or an MCP tool has this shape:

```json
{
  "ok": false,
  "code": "VIEWER_SIGN_IN_REQUIRED",
  "message": "This app is private. Sign in with the email it was shared with to open it.",
  "fix": "Sign in in the Uarpie viewer with the email address the owner invited, then open the app again.",
  "file": "<where to edit, when known>",
  "retryable": true,
  "docs": "https://docs.uarpie.app/errors/VIEWER_SIGN_IN_REQUIRED"
}
```

Apply `fix` (edit `file` when it is given), then run the same command again.