diff --git a/fmn/lib/models.py b/fmn/lib/models.py
index d2f3fc1..f47f4fd 100644
--- a/fmn/lib/models.py
+++ b/fmn/lib/models.py
@@ -300,6 +300,17 @@ def create_from_code_path(cls, session, valid_paths, code_path,
         session.commit()
         return rule
 
+    def set_argument(self, session, key, value):
+        args = self.arguments
+        args[key] = value
+        self.arguments = args
+        session.flush()
+        session.commit()
+        self.notify(
+            self.filter.preference.openid,
+            self.filter.preference.context.name,
+            "filters")
+
     def title(self, valid_paths):
         root, name = self.code_path.split(':', 1)
         return valid_paths[root][name]['title']
@@ -355,6 +366,18 @@ def fired(self, session):
             if pref:
                 self.notify(pref.openid, pref.context_name, "filters")
 
+    def get_rule(self, session, code_path, **kw):
+        for r in self.rules:
+            if r.code_path == code_path:
+                return r
+        raise ValueError("No such rule found: %r" % code_path)
+
+    def has_rule(self, session, code_path, **kw):
+        for r in self.rules:
+            if r.code_path == code_path:
+                return True
+        return False
+
     def add_rule(self, session, paths, rule, **kw):
         if isinstance(rule, basestring):
             rule = Rule.create_from_code_path(session, paths, rule, **kw)