Real AI agent use cases, with sources and setup prompts

Find real bugs with a vibe-coded fuzzer

A team vibe-coded a fuzzer and pointed it at FFmpeg.

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Source

dclavijo on Hacker News · 2026-08-27 · Project link

Written in our own words. Credit to the original author. Link checked 2026-10-14.

What they did

A team vibe-coded a fuzzer and pointed it at FFmpeg.

Result (as claimed)

Found a division by zero bug in FFmpeg.

Tools they used

The source does not name specific tools.

Cost: Pricing depends on the tools you pick; check each official pricing page.

Set it up

  1. Pick a contained repo or task

    Start on a branch or side project where mistakes are cheap.

  2. Install and configure

    Set up the tools you choose. Read what it can run on your machine and limit permissions where possible.

  3. Run it on a real task

    Give it a well-scoped issue and let it work. Review the diff like any pull request.

  4. Add guardrails

    Keep tests and CI in the loop, and never let an agent push to main or touch production secrets unattended.

Copy the full setup prompt

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Goal: Find real bugs with a vibe-coded fuzzer
What the original author did: A team vibe-coded a fuzzer and pointed it at FFmpeg.
Reported result (as claimed by the author): Found a division by zero bug in FFmpeg.
Source: https://news.ycombinator.com/item?id=49468642
Tools they used: not named in the source
Category: Dev & ops

Please:
1. Ask me 3 short questions about my situation (accounts I have, budget, what I want the output to look like).
2. Propose a step-by-step plan using these tools or cheaper alternatives, with the time and cost of each step. Use official pricing pages; say "check pricing" if unsure.
3. Then do the setup with me one step at a time, waiting for my OK before anything that sends messages, posts publicly, spends money or deletes data.
4. Finish with a checklist to run it again next time.

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