Independent guide based on upstream documentation reviewed October 10, 2026. Installation routes and tool capabilities below are documented by their authors; this site has not tested every agent or asset workflow.
Understand the baseline tools
- Git retrieves the toolkit and tracks source changes. Record the upstream commit and keep your own mod source separate from private game data.
- Python 3.10+ is declared by the upstream Python package. Its dependencies include Pillow, NumPy and PyYAML; the toolkit’s uv-based setup manages these for its CLI.
- ffmpeg supports recording and video-processing parts of the workflow. A simple code milestone can be reviewed before creating a showcase video.
- uv is recommended upstream. The README also lists uv tool install for the CLI, with pipx as an alternative installation route.
Verify the terminal the agent will actually use
Run git --version, python --version and ffmpeg -version in the same environment used for the task. On some systems the Python executable is named python3. Confirm um --help after installing the CLI. Save the detected versions and any missing-tool error in your preparation notes.
A terminal opened before an installation can retain an older PATH. If a program works in one window but not the agent’s shell, check the executable location and reopen that shell before replacing the installation. Windows games can be driven natively or from WSL according to the README; paths and installed tools still need checking in the environment you choose.
Add the game-specific build tools
Universal Modder’s general prerequisites do not replace the requirements of a mod loader. Our pinned Minecraft Java 1.21.1 case uses NeoForge with JDK 21. The Minecraft-in-GTA example instead uses Fabric with JDK 25 and MSVC tools for its GTA component. These belong to different workspaces.
The Terraria example uses tModLoader and its build tooling. Match the game edition, loader release and documented SDK before copying build commands. A current game update may differ from the field note, so record that mismatch as pending verification instead of assuming that newer means compatible.
Blender and asset services are conditional
Blender is needed when um render3d converts a 3D model into sprite frames. The upstream pipeline looks for blender on PATH or an explicit BLENDER setting. A first task using a hand-drawn 2D placeholder does not require that rendering stage.
fal needs a provider key for its hosted generation calls. Local ComfyUI is a separate image-generation route and needs its own running server and suitable model setup. Neither is necessary just to prepare a project checklist. Choose your asset route after the code’s first milestone works.
Define readiness with a small test
A useful readiness check is more concrete than a long list of installed programs: the agent reads the relevant instructions, the CLI opens, the chosen loader project builds, and a harmless change loads in a separate test profile. Back up saves before modded launches. Keep logs and a removal path, then add recording or polished art when the first feature is reviewable.
A starter prompt for your agent
Prepare a requirements checklist for my exact game, version, system and agent. Check Git, Python 3.10+ and um CLI access in the active shell, then list the chosen loader’s SDK separately. Explain whether ffmpeg, Blender, fal or local ComfyUI are needed for this milestone. Start with placeholder art and one build-and-load check. Record missing tools without assuming compatibility for other versions.