When tracking down unexpected cooked assets in Unreal Engine, one of the most useful hidden debugging options is the -cookshowinstigators=true argument.

By default, the cook process only tells you what asset is being cooked. It does not explain why that asset was included. In large projects, especially with indirect references, plugins, or accidentally hard-linked content, this can make debugging cook size and dependency issues extremely painful.

You can enable detailed reference tracing with:

-run=Cook -cookshowinstigators=true

When enabled, the cooker prints the instigator responsible for each asset being added to the cook. This helps identify:

• Unexpected hard references
• Assets pulled in through Blueprint dependencies
• Plugin content being cooked unintentionally
• Circular or indirect asset chains
• Why a supposedly unused asset still appears in packaged builds

Example cook command:

UnrealEditor-Cmd.exe MyProject.uproject -run=Cook -TargetPlatform=Win64 -cookshowinstigators=true

The output log will now include additional lines explaining which package or object requested each asset.

This argument is especially useful when:

• Optimizing package size
• Investigating long cook times
• Cleaning unused content
• Debugging Asset Manager rules
• Tracking dependency explosions after a refactor

Because the output can become very verbose, it is usually best used on focused cooks or while reproducing a specific issue rather than during normal CI packaging workflows.