UE Animation System

Target engine: UE 5.8. APIs below are verified against the 5.8 headers; older forms are listed under "Deprecated — do not use".

Covers the runtime animation path in the Engine module — UAnimInstance, FAnimInstanceProxy, UAnimMontage, UAnimNotify/UAnimNotifyState, curves, blend spaces, anim state machines, linked anim layers and root motion — plus the animation plugins shipped in 5.8 (PoseSearch, MotionWarping, Chooser, IKRig, ControlRig, BlendStack, OptimusCore, UAF). Build.cs: Engine for everything under Runtime/Engine/Classes/Animation, AnimGraphRuntime for the helper anim nodes such as FAnimNode_LayeredBoneBlend; plugin module names are listed per row below.

Context

Read .agents/ue-project-context.md if it exists (module names, conventions, enabled plugins, GAS/networking setup). Do not stop if it is missing.

Identify the area from the request and the codebase. Ask only when two plausible readings would produce different code.