Python editor workflows

Enable and version

Enable Python Editor Script Plugin and usually Editor Scripting Utilities, then restart. Unreal 5.8 embeds Python 3.11.8. Epic labels Python Editor scripting Experimental.

Python is available only in the editor—not PIE, Standalone Game, or cooked executables. Put project modules in Content/Python; init_unreal.py in a configured Python path runs when the editor detects it. Keep automatic initialization lightweight.

Execution selector

• Output Log Python mode: exploration and one-line inspection.
• File > Execute Python Script: manual repeatable script.
• -ExecutePythonScript="path": full editor, startup level loaded, then script.
• -run=pythonscript -script="path": faster commandlet/headless path; levels are not loaded automatically.
• Startup Scripts: run after the default startup level loads.

Epic warns against putting py ... inside startup -ExecCmd; it can execute before the editor environment is ready.

API pattern

import unreal

assets = unreal.get_editor_subsystem(unreal.EditorAssetSubsystem)
actors = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)

Inspect the generated 5.8 Python API for the exact subsystem/method available in the enabled plugins. The reflected unreal module changes with plugins and project C++ exposure.

Use get_editor_property() and set_editor_property() for reflected editor fields. The setter triggers pre/post-edit behavior that direct Python attribute assignment may skip.

Batch shape

Implement discover -> plan -> apply -> save -> validate -> report. Take explicit paths/filters as arguments; do not depend on current selection in unattended jobs. Return a nonzero process status or raise on hard failure so CI cannot misread a partial batch as success.

Use unreal.ScopedSlowTask for long interactive batches and honor cancellation. Use structured logs with object path, operation, status, and diagnostic.