Two-Factor Authentication
A password alone isn't enough for accounts that matter.
What it adds
TOTP-based 2FA with recovery codes.
What your agent is told to do
4
What your agent is told to do
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Use TOTP (authenticator apps). SMS is better than nothing but is defeated by SIM swapping — don't make it the only option.
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Generate single-use recovery codes at setup and make the user save them. This is the difference between a locked account and a support ticket.
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Require the current password before enabling or disabling 2FA.
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Verify a code during setup before you turn it on — otherwise a misconfigured app locks the user out instantly.
Edge cases it handles
6
Edge cases it handles
6- Accept a small time window (±1 period) for clock drift, but no more.
- A used TOTP code must not be replayable within its window.
- Recovery codes must be single-use, hashed at rest, and regenerable.
- Enabling 2FA should invalidate other active sessions.
- Rate-limit code attempts — six digits is brute-forceable otherwise.
- Don't lock a user out permanently; define the account recovery path before you ship.
Definition of done
8
Definition of done
8- TOTP setup verifies a code before enabling.
- Recovery codes are generated, hashed, single-use, and regenerable.
- The current password is required to enable or disable.
- Code attempts are rate-limited and codes can't be replayed.
- Clock drift is tolerated within one period.
- A documented account recovery path exists.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Upload Malware Scanning
Upload Malware Scanning
Quarantine uploaded files until they are known safe.
What it does
A quarantine lifecycle for uploads: every new file is unreachable until scanned, with defined handling for scanner failures and infected results.
How it works
- 1 Give every upload an explicit scan state — pending, clean, infected, or error — and default it to pending the moment the bytes land.
- 2 Make pending and infected files unreachable from every access path in the app, including admin views, previews, thumbnails, and any signed URL. A quarantine with one exception is not a quarantine.
- 3 Scan asynchronously and update the state; do not block the upload request on the scanner.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/upload-malware-scanning
Rate Limiting
Rate Limiting
Stop one client from ruining it for everyone.
What it does
Throttling on the endpoints that get abused: auth, search, exports, and public forms.
How it works
- 1 Identify the endpoints worth protecting: sign-in, sign-up, password reset, search, exports, and anything unauthenticated.
- 2 Limit by a stable identifier — user ID where signed in, IP otherwise. Be aware IP is shared behind NAT and proxies.
- 3 Return 429 with a Retry-After header. Do not silently drop the request.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/rate-limiting
Password Generator
Password Generator
Offer a strong password in one click wherever someone sets or changes credentials.
What it does
A generate control on password fields that produces a strong value, shows it, and hands it to the user safely.
How it works
- 1 Add the control to every place a password is set: sign-up, password change, password reset completion, and any admin screen that provisions credentials for someone else.
- 2 Generate the value in the browser using the platform's cryptographic random source. The value must never be produced on the server or sent anywhere.
- 3 Reveal the generated password by default so the user can record it, and offer a regenerate control beside it. A hidden generated password that the user cannot see is a password they will immediately reset.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/password-generator
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.