For a new asset, deliver an editable .blend, a runtime GLB, and a preview render. Follow the project's asset location, scale, axes, naming, and material conventions. For export-only tasks, leave the source untouched.
Run Blender
Find the executable on PATH or in its usual location (macOS /Applications/Blender.app/Contents/MacOS/Blender, Windows Program Files/Blender Foundation) and check --version. bpy exists only in Blender's bundled Python, so run scripts through Blender; put an existing .blend before --python:
<blender> --background [<SOURCE.blend>] --python-exit-code 1 --python <SCRIPT.py>
Save new sources explicitly with bpy.ops.wm.save_as_mainfile. Name datablocks explicitly and select shader nodes by type, because default node labels follow Blender's UI language. Bake procedural shading that glTF cannot represent.
Export
Use the bundled helper (path relative to this Skill):
<blender> --background <SOURCE.blend> --python-exit-code 1 --python <SKILL_DIR>/scripts/export_glb.py -- --output <ASSET.glb> [--collection <NAME>] [--apply-modifiers] [--overwrite]
It exports the scene's visible objects, or a named collection with its child collections, without cameras or lights. It refuses to replace an existing file without --overwrite, never saves the .blend, and prints a JSON summary. Keep every required mesh, armature, and parent in scope and presentation-only objects out of it. --apply-modifiers bakes modifiers but drops shape keys; leave it off for morph targets. glTF converts axes; do not add an extra rotation.
Verify
Render a preview and read the image. Load the GLB in the target engine and check scale, orientation, pivot, materials, textures, and animation. Without a target engine, reimport it into a clean Blender scene and report the runtime check as pending.