Capnp for a knowledge base

entity.capnp

struct Entity {
  type @0 :EntityType;

  union {
    id @0 :Text;
    blob @1 :Text;
    text @1 :List(Text);
  }
}

enum EntityType {
  BLOB @0;
  PERSON @1;
  ORGANISATION @2;
  TEXT @3;
  URL @4;
  TIMESTAMP @5;
  LOCATION @6;
}