Before you install
You need Git, Python 3.10+ and ffmpeg, plus access to your chosen AI agent. Install a game you own and identify whether you will use Windows natively or WSL. Blender is needed only for the 3D-to-sprite route.
Check these tools in the terminal where your agent will run. Successful checks show versions rather than “command not found.”
git --version
python --version
ffmpeg -versionOn systems where Python is named python3, check python3 --version. The Python interpreter used to install the CLI must meet the requirement. A game-specific example may require a newer Python, Java, .NET or compiler version.
Choose your agent
The following routes are listed in the upstream README, reviewed on October 10, 2026. Client support can change; if an instruction fails, check the linked source rather than substituting guessed commands.
| Agent | Where / installation route |
|---|---|
| Claude Code | Inside Claude Code /plugin marketplace add rehan-remade/universal-modder /plugin install universal-modder@universal-modder |
| Codex | Terminal / Codex CLI codex plugin marketplace add rehan-remade/universal-modder codex plugin add universal-modder@universal-modder |
| Gemini CLI | Terminal gemini extensions install https://github.com/rehan-remade/universal-modder |
| VS Code / Copilot | VS Code command palette Enable chat.plugins.enabled, run Chat: Install Plugin From Source, and enter https://github.com/rehan-remade/universal-modder. |
| Cursor | Marketplace or local clone Use the Cursor Marketplace route listed upstream, or clone the repository and open its directory. Cursor reads AGENTS.md and .cursor/mcp.json. |
| OpenCode | Terminal inside a clone opencode |
| Skills only | Terminal npx skills add https://github.com/rehan-remade/universal-modder |
| Any other agent / clone | Terminal git clone https://github.com/rehan-remade/universal-modder cd universal-modder |
Claude Code
Inside Claude Code
These are slash commands entered in Claude Code, not ordinary shell commands. Add the marketplace first, then install the plugin.
/plugin marketplace add rehan-remade/universal-modder
/plugin install universal-modder@universal-modderCodex
Terminal / Codex CLI
These commands use the Codex CLI. If your client does not recognize the plugin subcommand, check its version and current plugin support before using the clone route.
codex plugin marketplace add rehan-remade/universal-modder
codex plugin add universal-modder@universal-modderGemini CLI
Terminal
Use the extension installer, then start a session in a directory appropriate for your mod work.
gemini extensions install https://github.com/rehan-remade/universal-modderVS Code / Copilot
VS Code command palette
Enable chat.plugins.enabled, run Chat: Install Plugin From Source, and enter https://github.com/rehan-remade/universal-modder.
Cursor
Marketplace or local clone
Use the Cursor Marketplace route listed upstream, or clone the repository and open its directory. Cursor reads AGENTS.md and .cursor/mcp.json.
OpenCode
Terminal inside a clone
Clone first, then start OpenCode in the cloned directory. Its opencode.json supplies the skill paths and fal MCP configuration.
opencodeSkills only
Terminal
This route requires Node.js and npx. Treat it as a skills-only installation; verify the CLI and MCP configuration separately.
npx skills add https://github.com/rehan-remade/universal-modderAny other agent / clone
Terminal
Start your agent inside this directory so it can discover project instructions and configuration.
git clone https://github.com/rehan-remade/universal-modder
cd universal-modderInstall and verify the um CLI
The upstream README says plugin installations and clones place um on PATH. Verify that in your agent’s shell; do not assume it happened just because the repository exists.
um --help
um scan --helpExpected result: CLI help with available commands and scan options. For a separate CLI installation, use one of these upstream methods after installing uv or pipx:
uv tool install git+https://github.com/rehan-remade/universal-modderAlternative:
pipx install git+https://github.com/rehan-remade/universal-modderChoose one method. Open a new terminal afterward and repeat um --help. This verifies that the CLI can start; it does not yet prove that your game can be modded.
Set up assets: fal or local ComfyUI
fal API key
Get a key from your fal dashboard. It is used by the fal MCP server and um fal. Keep it out of commits, screenshots and published mod packages.
In a Bash-compatible shell, including WSL:
export FAL_KEY="YOUR_FAL_API_KEY"In PowerShell, the equivalent session environment setting is:
$env:FAL_KEY = "YOUR_FAL_API_KEY"Replace the placeholder locally. Launch your agent from that environment; an already running editor may need to be restarted. The setting above is for the current shell session. Asset calls can incur charges; review the selected model and pricing before generation.
Local images without a fal key
If you already run a local ComfyUI server, um comfy offers an image workflow without a fal API key. ComfyUI still requires its own server, models and suitable hardware. It is not a replacement for every hosted 3D, audio or video operation.
um comfy --help
um comfy statusIf status cannot reach a server, confirm ComfyUI is running and review the help for connection settings. You can defer asset generation while investigating a game or building an initial code-only change.
Confirm your setup and start a session
- CLI: confirm
um --helpruns in the agent’s actual shell. - Skills: ask your agent to locate the mod-any-game skill and summarize its safety rules.
- Configuration: for a clone, inspect the matching MCP configuration. AGENTS.md contains shared instructions; CLAUDE.md and GEMINI.md point to it.
- Recon: ask for an inventory and plan before approving any game changes.
Clone layouts include .agents/skills and .claude/skills. MCP configuration is agent-specific: .mcp.json, .codex/config.toml, .cursor/mcp.json, .vscode/mcp.json or opencode.json.
Installation troubleshooting
um: command not found
Open a new terminal, check that you are in the same Windows or WSL environment used for installation, and inspect the installer’s output. A bare clone may not have completed the expected bootstrap in your agent environment. Use the explicit uv or pipx CLI install above if needed.
On Bash-compatible shells, use command -v um. On PowerShell, use Get-Command um. If the install succeeded but neither locates it, follow your installer’s PATH instructions rather than guessing a directory.
The plugin or extension command is not recognized
Check where you entered it: Claude slash commands belong in Claude Code; Codex and Gemini CLI commands belong in a terminal. Confirm your agent client supports the install route. The upstream clone route is an alternative when a plugin route is unavailable.
The agent cannot find the skills
For a clone, start the agent inside the repository instead of its parent directory. Check that the relevant skill directory is present and that the agent has loaded project instructions. Skills-only installs may have separate destinations chosen during installation.
fal reports a missing key
Make sure the agent process inherits FAL_KEY from the shell where you set it. Do not print the key in a shared transcript. If the variable is available, inspect the service error for authentication, credits or model-access issues.
The scan does not find my game
A custom library location or an environment boundary may be involved. Read um scan --help for supported inputs and give the agent the actual game directory. Do not invent a path flag. A found game is still subject to route and version checks.
Can I follow the same steps on macOS or Linux?
The CLI’s Python requirement is separate from the game’s platform. Windows automation and game-specific loaders may require Windows or WSL. Check your chosen example’s requirements before treating these instructions as a cross-platform compatibility claim.