01 / Pick a game and a tiny idea
A good first mod adds one item or changes one value. A complete new world or cross-game mashup has too many moving parts for the first session.
If you have Terraria and tModLoader installed, try one new weapon with a placeholder sprite. For a data-driven game, try a single reversible unit or item change. Use the game directory to find a documented starting route.
First choose your agent in the installation guides. The toolkit and the game’s mod loader are separate pieces.
02 / Inspect before editing
Tell the agent where the game is installed. Ask it to search prior field notes, identify the exact game and loader versions, and explain its recommended route. An engine name alone is not enough.
Inspect my game at [your local game folder]. Search the Universal Modder knowledge base first. Identify the game version, engine, current loaders, save folders, and a small modding route. Explain your plan and do not change files yet.For a knowledge-base search you can inspect yourself:
um kb search "terraria"03 / Set up a test lab
Use a separate test world or save and have the agent back up existing saves before touching them. Record which files will change, where the mod will live, and how to remove it.
Review a proposed loader installation or any action that changes a game folder. Avoid introducing several loader or game updates at the same time.
04 / Build one working slice
Have the agent read the relevant API or actual code before implementing. Keep the first build focused on behavior; a placeholder image is enough to test an item or weapon.
Using the route we agreed on, make a minimal mod with one new weapon. Use a placeholder sprite. Explain the expected in-game behavior, build the mod, and report any build errors. Keep the change reversible.
Once the minimal version works, add final art or sound. Confirm any paid generation
before the agent submits it. The toolkit includes um fal for fal workflows
and um comfy for local ComfyUI images.
05 / Verify inside the game
A successful build is only the beginning. Check that the game loads, the item appears, its behavior matches your idea, and the save still loads after a restart. If something fails, capture the exact error and the relevant game or loader log.
Have the agent distinguish what it actually tested from what it expects to work. Review any request to drive your mouse and keyboard before letting it control the running game.
Something went wrong? Start here06 / Package and keep the useful notes
Include your mod source or permitted patch, your own assets, dependency versions, and removal instructions. Do not bundle original game files, decompiled dumps, or API keys.
um publish check --helpRecord the game version, route, test results, and any fixes. If you want to contribute a field note, follow the upstream contribution instructions and review the final submission before publishing it.