curl --request GET \
  --url http://localhost:3917/diagnose

{
  "entity_count": 3,
  "info": [
    "Physics: 1 Dynamic, 0 Kinematic, 2 Static"
  ],
  "warning_count": 1,
  "warnings": [
    "E3: has Velocity but no PhysicsBody — physics won't integrate"
  ]
}