diff --git a/syndicate/actor.rkt b/syndicate/actor.rkt
index 3c6a4db..1f6d865 100644
--- a/syndicate/actor.rkt
+++ b/syndicate/actor.rkt
@@ -59,9 +59,13 @@
 (require "field.rkt")
 (require "support/counter.rkt")
 
-(struct entity (assert retract message sync))
+(struct entity (id assert retract message sync)
+  #:methods gen:custom-write
+  [(define (write-proc e port mode)
+     (fprintf port "#<entity:~a>" (entity-id e)))])
 (define-struct-defaults make-entity entity
-  (#:assert [entity-assert #f]
+  (#:_id [entity-id (generate-entity-id)]
+   #:assert [entity-assert #f]
    #:retract [entity-retract #f]
    #:message [entity-message #f]
    #:sync [entity-sync #f]))
@@ -108,6 +112,7 @@
 
 ;;---------------------------------------------------------------------------
 
+(define generate-entity-id (make-counter))
 (define generate-actor-id (make-counter))
 (define generate-turn-id (make-counter))
 (define generate-handle (make-counter))