---
title: "Discussion on \"Hardening a free public AI tool against prompt injection in 2 hours\" | Hashnode"
description: "Discussion on \"Hardening a free public AI tool against prompt injection in 2 hours\". I shipped a free public AI cover-letter roast tool. Within hours I realised it was a prompt-injection target. Here are the seven layers of defense I bolted on, what each one prevents, and which ones every public AI tool needs."
url: "https://hashnode.com/posts/hardening-a-free-ai-tool-against-prompt-injection-in-two-hours/69f8cfd313556e536f79b535"
---

[Feed](https://hashnode.com/feed) /

Discussion

# [Hardening a free public AI tool against prompt injection in 2 hours](https://vantage-labs.hashnode.dev/hardening-a-free-ai-tool-against-prompt-injection-in-two-hours?utm_source=hashnode&utm_medium=feed)

I shipped a free public AI cover-letter roast tool. Within hours I realised it was a prompt-injection target. Here are the seven layers of defense I bolted on, what each one prevents, and which ones every public AI tool needs.

May 4 · 7 min read · vantage-labs.hashnode.dev  
Read the article

-   [#founder-journal](https://hashnode.com/tag/founder-journal)
-   [#ai-security](https://hashnode.com/tag/ai-security)
-   [#building-in-public](https://hashnode.com/tag/building-in-public)
-   [#engineering](https://hashnode.com/tag/engineering)
-   [#prompt-injection](https://hashnode.com/tag/prompt-injection)

## Written by

[Giovanni Sizino Ennes](https://hashnode.com/@vantagelabs)

@vantagelabs · London, UK

  
[View profile](https://hashnode.com/@vantagelabs)

Founder of AimVantage — AI job prep in 90 seconds.

Building AimVantage (formerly Vantage AI) — AI job preparation for UK job seekers. Upload CV, paste job link, get full prep pack (company intel, tailored cover letter, mock interview, CV fit score) in 90 seconds. Free at aimvantage.uk.

## Responses

Markdown supported · ⌘↵ to post

No responses yet.