diff --git a/code/artifact.js b/code/artifact.js
index 8d61552b..28b61b3a 100644
--- a/code/artifact.js
+++ b/code/artifact.js
@@ -70,9 +70,11 @@ window.artifact.processData = function(data) {
     return;
   }
 
+  var oldArtifacts = artifact.entities;
   artifact.clearData();
 
   artifact.processResult(data.result);
+  runHooks('artifactsUpdated', {old: oldArtifacts, 'new': artifact.entities});
 
   // redraw the artifact layer
   artifact.updateLayer();
diff --git a/code/hooks.js b/code/hooks.js
index 26c4bb9d..9629647e 100644
--- a/code/hooks.js
+++ b/code/hooks.js
@@ -52,10 +52,12 @@
 //              this only selects the current chat pane; on mobile, it
 //              also switches between map, info and other panes defined
 //              by plugins
+// artifactsUpdated: called when the set of artifacts (including targets)
+//              has changed. Parameters names are old, new.
 
 window._hooks = {}
 window.VALID_HOOKS = [
-  'portalSelected', 'portalDetailsUpdated',
+  'portalSelected', 'portalDetailsUpdated', 'artifactsUpdated',
   'mapDataRefreshStart', 'mapDataEntityInject', 'mapDataRefreshEnd',
   'portalAdded', 'linkAdded', 'fieldAdded',
   'publicChatDataAvailable', 'factionChatDataAvailable',