diff --git a/lib/didkit/plc_operation.rb b/lib/didkit/plc_operation.rb
index 4b4fbef..4bf8485 100644
--- a/lib/didkit/plc_operation.rb
+++ b/lib/didkit/plc_operation.rb
@@ -12,7 +12,7 @@ class FormatError < StandardError
     include AtHandles
     include Services
 
-    attr_reader :json, :did, :created_at, :type, :handles, :services
+    attr_reader :json, :did, :cid, :created_at, :type, :handles, :services
 
     def initialize(json)
       @json = json
@@ -20,6 +20,10 @@ def initialize(json)
       raise FormatError, "Missing DID: #{json}" if @did.nil?
       raise FormatError, "Invalid DID: #{@did}" unless @did.is_a?(String) && @did.start_with?('did:')
 
+      @cid = json['cid']
+      raise FormatError, "Missing CID: #{json}" if @cid.nil?
+      raise FormatError, "Invalid CID: #{@cid}" unless @cid.is_a?(String)
+
       timestamp = json['createdAt']
       raise FormatError, "Missing createdAt: #{json}" if timestamp.nil?
       raise FormatError, "Invalid createdAt: #{timestamp.inspect}" unless timestamp.is_a?(String)