Unreal Packaging Agent Skill

Unreal Packaging & Cooking

Turn a UE5 project into a runnable, distributable build: choose the right build configuration,

cook content, set the launch map, and package — from the editor or the command line. Targets

UE 5.4+.

When to use

• Use when producing a build (test or release), choosing Development vs Shipping, cooking

content, configuring Packaging / Maps & Modes settings, or automating builds with

RunUAT BuildCookRun for CI.

• Use when the project has a *.uproject and Config/Default*.ini, and the goal is a packaged

player rather than running in-editor.

When *not* to use: storefront submission/release process → steam-publish / itch-publish.

Editor-time gameplay/iteration is not packaging.

Core workflow

• Set the launch map. Project Settings → Maps & Modes → Game Default Map is what a

packaged build loads first. Wrong/empty here is the most common "packaged game is black"

cause.

• Pick the build configuration: Development (default; optimized but keeps logging/

stats/console for testing) vs Shipping (all optimizations, debugging tools stripped — for

release). DebugGame/Debug are for debugging engine/game code and aren't for distribution;

DebugGame isn't available for Blueprint-only projects.

• Understand cook vs package. Cooking converts assets to the target platform's format

and packs them into .pak files. Packaging bundles the compiled executable + cooked

content into a standalone, distributable set of files. Packaging runs a cook as part of it.

• Package from the editor: the Platforms menu → choose the platform (e.g. Windows) →

set the Binary Configuration → Package Project → pick an output folder.

• Or build from the command line with the Unreal Automation Tool (RunUAT BuildCookRun)

for repeatable/CI builds.

• Tune Packaging settings (Project Settings → Packaging): which maps/directories to

cook, full-rebuild, compression, and whether to build all maps.

• Verify by *running the packaged build*, not just by a successful cook — launch the

executable and confirm it loads the right map and runs.

Patterns

1. Editor packaging (the menu path)

Platforms (toolbar)
  -> Windows
     -> Binary Configuration -> Development | Shipping
     -> Content Management -> Package Project
  -> choose/confirm the staging output folder

2. Command-line build with UAT (CI-friendly)

# Cook + build + stage + pak + archive a Shipping Windows build.
RunUAT BuildCookRun \
  -project="C:/Path/MyGame.uproject" \
  -noP4 -platform=Win64 -clientconfig=Shipping \
  -cook -allmaps -build -stage -pak -archive \
  -archivedirectory="C:/Builds/MyGame"

RunUAT lives in Engine/Build/BatchFiles/ (RunUAT.bat on Windows, RunUAT.sh on

macOS/Linux). Drop -allmaps and pass -map=Map1+Map2 to cook a subset.

3. Cook only (no packaging), e.g. to refresh content

RunUAT BuildCookRun -project="C:/Path/MyGame.uproject" -noP4 \
  -platform=Win64 -clientconfig=Development -cook -skipstage

Pitfalls

• Packaged build loads a black/empty level — Game Default Map isn't set (or that map wasn't

cooked). Set it in Maps & Modes and ensure it's included in the cook.

• Shipping a Development build — Development keeps logging/console/stats and is slower; ship

Shipping. Conversely, Shipping strips UE_LOG/console, so debugging a Shipping-only issue

needs Development or Test.

• A referenced map/asset is missing at runtime — it wasn't cooked. Add it to the Packaging

settings' maps/directories to cook, or cook all maps.

• Build fails on the platform — the platform SDK/toolchain isn't installed (Windows build

tools, Android SDK/NDK, console SDKs). Install the platform's prerequisites.

• Expecting Blueprint Nativization — it was removed in UE5; don't rely on it for

performance. Profile and move hot logic to C++ (unreal-cpp-gameplay) instead.

• First cook is very slow — shaders and all assets cook from scratch; subsequent cooks are

incremental. Don't mistake a slow first cook for a hang.

References

• Primary docs: "Packaging Your Project"

(https://dev.epicgames.com/documentation/en-us/unreal-engine/packaging-your-project) and the

Build Configurations / BuildCookRun references.

Related skills

• steam-publish / itch-publish — distributing the packaged build to a storefront.
• unreal-cpp-gameplay — moving hot logic to C++ now that BP nativization is gone.