Animation

The execution model is in blender-core (its references/bpy-patterns.md has verified keyframe/driver snippets). Rigs are in blender-character-rigging.

5.x data model (what changed)

• An Action holds slots (one per animated ID) and layers → strips → channelbags → F-curves. A single action can animate several objects (e.g. a rig and its camera) through different slots.
• Assign: ob.animation_data.action = act, then make sure ob.animation_data.action_slot is set (picked automatically when a suitable slot exists; otherwise act.slots.new(id_type="OBJECT", name=ob.name)).
• F-curves: cb = anim_utils.action_ensure_channelbag_for_slot(act, slot), then cb.fcurves.ensure(path, index=i, group_name=...). action.fcurves no longer exists.
• The simplest route is still pb.keyframe_insert("rotation_quaternion", frame=f), which creates the action, slot and channelbag.

Workflow (keyframe animation, studio style)

1. Blocking: key poses on every channel (CONSTANT interpolation, bpy.context.preferences.edit.keyframe_new_interpolation_type) on golden frames (contact, down, passing, up for walks).
2. Breakdowns: add in-betweens that define arcs and spacing.
3. Spline: switch to BEZIER, fix spacing in the Graph Editor, and clean overshoot. Auto-clamped handles avoid overshoot.
4. Polish: offsets/overlap (follow-through on hair, tails, cloth bones), arcs, moving holds (never a perfectly frozen character), and contact stability (feet locked with IK).
5. Review: MCP look(mode="frames", frame_count=8) or a Workbench playblast (blender-rendering).