CLI Reference

ModKit includes a CLI commandlet (ModKitBuild) for automating builds in CI/CD pipelines or scripting environments — no Editor GUI required.

Basic Usage

UnrealEditor-Cmd.exe MyProject.uproject -run=ModKitBuild <subcommand> [options]

Replace UnrealEditor-Cmd.exe with the full path to your UE installation's commandlet executable.

Subcommands

new — Create a Mod

Create a new mod project from the CLI.

UnrealEditor-Cmd.exe MyProject.uproject -run=ModKitBuild new \
  --modid=my_mod \
  --name="My Mod" \
  --author="YourName"

Option	Required	Default	Description
--modid	✅	—	Unique mod identifier (lowercase, underscores)
--name	—	Derived from ModId	Display name
--author	—	Unknown	Author name

The mod is created at {ProjectDir}/Plugins/{ModId}/. Remaining fields (version, min/max game version, tags) take defaults and can be edited afterward via ModDescriptor.json or the Edit Mod window.

Exit codes: 0 = success, 1 = error

---

validate — Validate a Mod

Validate a mod without building.

UnrealEditor-Cmd.exe MyProject.uproject -run=ModKitBuild validate \
  --mod=/path/to/Plugins/my_mod

Option	Required	Description
--mod	✅	Path to the mod plugin folder

Runs the same validation as the UI (descriptor check, hard references, Blueprint compile errors).

Exit codes: 0 = valid, 1 = validation errors found

---

build — Build a Mod to PAK

Cook and package a mod.

UnrealEditor-Cmd.exe MyProject.uproject -run=ModKitBuild build \
  --mod=/path/to/Plugins/my_mod \
  --platform=Windows \
  --output=/path/to/output

Option	Required	Default	Description
--mod	✅	—	Path to the mod plugin folder
--platform	—	Windows	Target platform: Windows, Mac, Linux
--output	—	{ProjectDir}/Saved/ModKitOutput	Output directory for the .pak file
--compress	—	true	Enable Oodle compression

Output file: {output}/{modid}_{platform}.pak

Exit codes: 0 = success, 1 = build failed

---

list — List Mods in a Game Directory

List all .pak files in a game's Mods directory.

UnrealEditor-Cmd.exe MyProject.uproject -run=ModKitBuild list \
  --game=/path/to/game

Option	Required	Description
--game	✅	Path to the game installation directory

Outputs a list of discovered .pak files and their ModId / Version if ModDescriptor.json is embedded.

Exit codes: 0 = success, 1 = game directory not found

---

CI/CD Example

GitHub Actions workflow to build and validate a mod on every push:

name: Build Mod

on: [push, pull_request]

jobs:
  build:
    runs-on: windows-latest
    steps:
      - uses: actions/checkout@v3

      - name: Validate
        run: |
          & "C:\Program Files\Epic Games\UE_5.4\Engine\Binaries\Win64\UnrealEditor-Cmd.exe" `
            "${{ github.workspace }}\MyModWorkspace.uproject" `
            -run=ModKitBuild validate `
            --mod="${{ github.workspace }}\Plugins\my_mod"

      - name: Build
        run: |
          & "C:\Program Files\Epic Games\UE_5.4\Engine\Binaries\Win64\UnrealEditor-Cmd.exe" `
            "${{ github.workspace }}\MyModWorkspace.uproject" `
            -run=ModKitBuild build `
            --mod="${{ github.workspace }}\Plugins\my_mod" `
            --output="${{ github.workspace }}\output"

      - name: Upload PAK
        uses: actions/upload-artifact@v3
        with:
          name: my_mod
          path: output/*.pak

Logging

All CLI output uses structured log categories:

Category	Content
LogModKitCLI	Commandlet execution, subcommand routing
LogModKitBuild	Cook, PAK, pipeline stages
LogModKitValidator	Validation results

Add -log to the command line for full verbose output:

UnrealEditor-Cmd.exe MyProject.uproject -run=ModKitBuild build --mod=... -log