Real AI agent use cases, with sources and setup prompts

Turn your personal website into a playable game

Rebuilt the Halo 3 map Guardian to run in the browser and hid a treasure hunt through his life inside it.

Free tierweeksAdvancedSource linked

Source

runshouse on Hacker News · 2026-09-16 · Project link

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

What they did

Rebuilt the Halo 3 map Guardian to run in the browser and hid a treasure hunt through his life inside it.

Result (as claimed)

Live as his personal site.

Tools they used

OpenAI Codex

Cost: OpenAI Codex: free plan, paid from $8/mo. Checked 2026-10-14.

Set it up

  1. Write a one-page brief

    Describe the app in plain words: who it is for, the 3 core screens or actions, and what "done" looks like.

  2. Start the project with your agent

    Open OpenAI Codex and paste the brief. Ask it to propose a stack and a file plan before writing code.

  3. Build one slice at a time

    Ship the smallest working flow first, run it, then add features one by one. Commit after each working step.

  4. Test it like a user

    Click through on desktop and phone. Ask the agent to add basic tests and fix anything that breaks.

  5. Check security and ship

    Keep keys in environment variables, check auth and database rules, then deploy and share the link.

Copy the full setup prompt

Paste into your agent and it will walk you through the setup, asking before anything that sends, posts or spends.

You are helping me set up this AI use case end to end in Claude Code.

Goal: Turn your personal website into a playable game
What the original author did: Rebuilt the Halo 3 map Guardian to run in the browser and hid a treasure hunt through his life inside it.
Reported result (as claimed by the author): Live as his personal site.
Source: https://news.ycombinator.com/item?id=49732259
Tools they used: OpenAI Codex
Category: Vibe coding & apps

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.

Related use cases