You do not write the mod yourself — an AI coding agent does. Your job is to pick two games you own, hand Melty’s generated instructions to the agent, describe the mashup you want, and test the result. Here is the full process, step by step.
Install the official Melty desktop app on Windows, then install both games you plan to combine. You need legitimate copies and any required launchers logged in. Have an AI coding agent ready in a project workspace with local file access — Melty names Claude Code and Codex as destinations, but any capable coding agent works.
In Melty’s Create screen, under My games, pick the two installed games and choose Mash with AI — a different action from the single-game Mod with AI option. Double-check the game names in the generated instructions, since button thumbnails may not match the highlighted cards.
Use Send instructions to coding agent and paste the text into your agent session. Review it before submitting: it typically includes the game names, detected install directories, and a publishing request. If you only want a local experiment, explicitly remove the publishing request and tell the agent not to publish. Keep the platform setup text rather than replacing everything.
Name which game provides the world, which mechanic you want from the other, and what a successful first test looks like. Answer the agent’s follow-ups about controls, camera, character, UI, and mechanics. A good brief asks the agent to explain feasibility before editing files, keep the first test small, and stop and explain any blocker instead of guessing.
Launch via the procedure your agent provides and check the interaction from your brief. If it fails, report what you did, the expected behavior, and the actual result, then re-test the same action. A mashup becomes visible in My mashups when published, but a release only goes live after Melty sees it running on your PC and it passes an audit — uploading is not instant approval.
The single biggest difference between a broken build and a fun one is the brief. A strong brief answers three questions up front: which game is the world, which mechanic is imported, and what does “working” look like in the first five minutes. For a Skyrim-meets-Minecraft style mashup, for example: the world is Skyrim, the mechanic is block placing and crafting, and success is chopping a tree in Whiterun and placing the wood as blocks.
Ask the agent to explain feasibility before touching files, keep the first test small, and stop with an explanation when something blocks it. Vague briefs produce vague builds.
New to Melty entirely? Start with what Melty is and how it works, then check whether Melty is safe to install.