UE Mass Entity

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

Mass is an archetype Entity Component System for simulating thousands of agents with cache-friendly data layouts and multi-threaded processors. The core lives in the always-available runtime modules MassEntity and MassCore (plus MassSignals, MassEngine); gameplay-facing pieces (spawning, representation, movement, LOD, replication, actor bridging) come from the MassGameplay (Experimental in 5.8) plugin, and navigation/behavior from MassAI (Experimental in 5.8) and MassCrowd (Experimental in 5.8).

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.