Show HN: LLMonster Rancher

2 points by alexwebb2 63 days ago | 3 comments

I've long held a bit of nostalgia for the old PlayStation game Monster Rancher.

You could "discover" monsters by popping in any arbitrary CD in your house – music, a PS game, a PC game, whatever – and it would generate a monster based on the disc's metadata, and add it to your ranch. It was a game about collecting, breeding, and battling these monsters.

The generated monster usually had nothing at all to do with the disc's content, of course. There were some specific discs that were hard-coded in that would give you a relevant monster, but not a ton.

It was a fairly niche thing, though, and the death of CDs sort of killed the whole idea.

But now in the age of LLMs, it feels like maybe the time has come back around for something like this to be pretty fun again, so I've implemented it as an Agent Skill that:

1. accepts a URL and reads the content (or any input, really) 2. follows some standard guidance on generating monster JSON for it 3. uses a Gemini image model to generate a monster avatar 4. renders it all in a fun little trading card image 5. allows you to breed them into hybrids, battle them, and share them to Github Gists

This was mainly a scratch-my-own-itch nostalgia indulgence. I briefly considered doing this as a full blown site, but agent skills give a fair bit more interactive flexibility while not costing me a dime. You can just point your agent (Claude Code, etc) to aiwebb/llmonster-rancher and tell it to get going.

Hope y'all have fun with it.

jameschaearley 62 days ago |

Monster Rancher was one of those games where half the fun was just raiding your parents' CD collection to see what you'd get. URLs are a solid stand-in for that.

I read through SKILL.md and liked how the type heuristics and stat scaling are structured as loose guardrails rather than rigid formulas. The "decide the vibe" step before any stats get generated is a good call -- it seems like that's what keeps the creatures from feeling like generic fantasy output. How much iteration did that take to land on? Did earlier versions skip that step and just go straight to stat generation?

throwaway12pol 63 days ago |

Seems pretty fun. Can I use it without image generation? Also, I think hosting it on a website would get it closer to Monster Rancher, as MR was deterministic while this project is not, I can generate a different Roko Basilisk even if I use the same URL you did. The website could enforce deterministic generation by generating only once and caching the results.

Will try this skill out later.

alexwebb2 63 days ago | |

Yeah, you could certainly tell it to skip the Gemini image gen step and replace with generated SVG art, or an existing image, or just stick a longer description there, whatever. It's flexible.

I thought about the deterministic generation aspect, but there's no "random seed" equivalent for frontier LLMs to my knowledge that would guarantee deterministic output (even temperature=0 is still nondeterministic).