Upload Malware Scanning
Quarantine uploaded files until they are known safe.
What it adds
A quarantine lifecycle for uploads: every new file is unreachable until scanned, with defined handling for scanner failures and infected results.
What your agent is told to do
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What your agent is told to do
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Give every upload an explicit scan state — pending, clean, infected, or error — and default it to pending the moment the bytes land.
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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.
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Scan asynchronously and update the state; do not block the upload request on the scanner.
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Decide and document what an infected file does: delete immediately, or retain for a fixed period for investigation. Both are defensible; an undefined policy is not.
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Tell the user their file was rejected in plain language. Do NOT surface the signature name, the scanner's raw output, or any internal file path — that hands an attacker a feedback loop for tuning their payload.
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Signed-URL issuance and download authorization are owned by Secure File Downloads. Extend that feature to consult scan state rather than building a parallel delivery path here.
Edge cases it handles
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Edge cases it handles
7- A scanner timeout or outage must fail closed — the file stays pending and inaccessible, and the backlog is retried and alerted on.
- Files larger than the scanner's limit need an explicit decision, not a silent pass.
- Archives can hide payloads several layers deep, and zip bombs expand catastrophically. Cap recursion depth and expansion ratio.
- A file already marked clean can become infected as signatures update. Support re-scanning existing storage.
- False positives need a human review path, or you will permanently delete a customer's legitimate file.
- A URL signed while a file was clean must stop working the moment it is marked infected.
- Uploads that never complete scanning must not accumulate as permanent pending clutter — expire them.
Definition of done
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Definition of done
8- Every uploaded file has a scan state and starts as pending.
- Pending and infected files return no bytes from any route, signed or otherwise.
- Scanner outages and timeouts leave files inaccessible rather than passing them through.
- The infected-file retention or deletion policy is written down and implemented.
- User-facing rejection messages contain no signature names or internal paths.
- A previously clean file can be re-scanned and revoked.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
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
Data Integrity Constraints
Data Integrity Constraints
Enforce your important rules in the database, not just in the form.
What it does
Database-level uniqueness, foreign key, check, and not-null constraints backing the business rules the application currently only validates in code.
How it works
- 1 Inventory the rules the app relies on — required fields, uniqueness, valid enum values, positive amounts, referential links — and note which exist only in application code.
- 2 Before adding each constraint, query for rows that already violate it and decide explicitly whether to fix, delete, or exclude them. Every mature database has violating legacy rows.
- 3 Add constraints in a way that does not hold a long exclusive lock: create indexes concurrently, add checks as NOT VALID and validate them in a second step.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/data-integrity-constraints
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.