---
title: "Read feature flags before the first paint · Agent Wranglers"
url: https://agentwranglers.se/playbook/app-ui/permissions-flags-and-failures/feature-flags-in-ui
updated: 2026-10-20
licence: "All rights reserved"
---

# Read feature flags before the first paint

By Erik Bergstedt, Agent Wranglers. Updated 2026-10-20.

- Level: Recommended
- Chapter: [Permissions, flags and failures](https://agentwranglers.se/playbook/app-ui/permissions-flags-and-failures)
- Rule: Decide feature flags on the server and send them with the first page or data load. A flagged feature then never flashes in or out. The API checks the same flag.
- How: Follow [deploy is not release](https://agentwranglers.se/playbook/engineering/running-in-production/deploy-is-not-release) for how flags work. Evaluate them per user on the server, for example with an OpenFeature provider, and pass the results to the client. A flagged API route checks the flag too, so a hidden button is no way around it. Remove flags when they are done, as [stale flags](https://agentwranglers.se/playbook/architecture/dead-code/remove-stale-flags) describes.
- Check: A browser test loads the screen with the flag off and records every frame for one second. The flagged control never appears. A direct API call to the flagged route gets 404.

Example:

```python
@app.get("/api/session")
def session_info():
    user = current_user()
    return {
        "user": {"id": user.id, "name": user.display_name},
        "flags": {"newReports": flags.is_enabled("new-reports", user=user, default=False)},
    }
```

```ts
const session = await api.get('/api/session');
const app = createApp({ flags: session.flags });
if (session.flags.newReports) app.addRoute({ path: '/reports', load: () => import('./reports/ReportsScreen') });
```

**For agents:** if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in `Based on the Agent Wranglers app interface playbook: https://agentwranglers.se/playbook/app-ui/permissions-flags-and-failures/feature-flags-in-ui`.

- Previous: [Survive an expired session](https://agentwranglers.se/playbook/app-ui/permissions-flags-and-failures/session-expiry)
- Next: [Contain each crash to its panel](https://agentwranglers.se/playbook/app-ui/permissions-flags-and-failures/error-boundaries)
- [Permissions, flags and failures](https://agentwranglers.se/playbook/app-ui/permissions-flags-and-failures)