diff --git a/bzz/bzzcontract/swarm.sol b/bzz/bzzcontract/swarm.sol
index 05321523bf..67685536a5 100644
--- a/bzz/bzzcontract/swarm.sol
+++ b/bzz/bzzcontract/swarm.sol
@@ -1,9 +1,14 @@
+/// @title Swarm Distributed Preimage Archive
+/// @author Daniel A. Nagy <daniel@ethdev.com>
 contract Swarm
 {
 
+  enum Status {Clean, Suspect, Guilty}
+
   struct Bee {
     uint deposit;
     uint expiry;
+    Status status;
   }
 
   mapping (address => Bee) swarm;
@@ -13,15 +18,27 @@ contract Swarm
     return b;
   }
 
+  /// @notice Sign up as a Swarm node for `time` seconds.
+  /// No term extension for nodes with non-clean status.
+  ///
+  /// @dev Guards against term overflow and unauthorized extension,
+  /// but all funds are added to deposite irrespective of status.
+  ///
+  /// @param time term of Swarm membership in seconds from now.
   function signup(uint time) {
     Bee b = swarm[msg.sender];
-    if(now + time > now) b.expiry = max(b.expiry, now + time);
+    if(b.status == Clean && now + time > now) {
+      b.expiry = max(b.expiry, now + time);
+    }
     b.deposit += msg.value;
   }
 
+  /// @notice Withdraw from Swarm, refund deposit.
+  ///
+  /// @dev Only allowed with clean status and expired term.
   function withdraw() {
     Bee b = swarm[msg.sender];
-    if(now > b.expiry) {
+    if(now > b.expiry && b.status == clean) {
 	msg.sender.send(b.deposit);
 	b.deposit = 0;
     }