diff --git a/brozzler/browser.py b/brozzler/browser.py
index 6b1c464..65765fd 100644
--- a/brozzler/browser.py
+++ b/brozzler/browser.py
@@ -629,11 +629,14 @@ class Browser:
                 ):
                     run_behaviors = False
 
+                behavior_outlinks: frozenset[str] = frozenset()
                 if run_behaviors and behavior_timeout > 0:
                     behavior_script = brozzler.behavior_script(
                         page_url, behavior_parameters, behaviors_dir=behaviors_dir
                     )
-                    self.run_behavior(behavior_script, timeout=behavior_timeout)
+                    behavior_outlinks = self.run_behavior(
+                        behavior_script, timeout=behavior_timeout
+                    )
                 final_page_url = self.url()
                 if on_screenshot:
                     if simpler404:
@@ -651,7 +654,7 @@ class Browser:
                     outlinks = self.extract_outlinks(timeout=extract_outlinks_timeout)
                 if run_behaviors and not skip_visit_hashtags:
                     self.visit_hashtags(final_page_url, hashtags, outlinks)
-                return final_page_url, outlinks
+                return final_page_url, outlinks.union(behavior_outlinks)
         except brozzler.ReachedLimit:
             # websock_thread has stashed the ReachedLimit exception with
             # more information, raise that one
@@ -869,7 +872,7 @@ class Browser:
         message = self.websock_thread.pop_result(msg_id)
         return message["result"]["result"]["value"]
 
-    def run_behavior(self, behavior_script, timeout=900):
+    def run_behavior(self, behavior_script, timeout=900) -> frozenset[str]:
         self.send_to_chrome(
             method="Runtime.evaluate",
             suppress_logging=True,
@@ -882,7 +885,7 @@ class Browser:
             elapsed = time.time() - start
             if elapsed > timeout:
                 self.logger.info("behavior reached hard timeout", elapsed=elapsed)
-                return
+                return frozenset()
 
             brozzler.sleep(check_interval)
 
@@ -890,7 +893,11 @@ class Browser:
             msg_id = self.send_to_chrome(
                 method="Runtime.evaluate",
                 suppress_logging=True,
-                params={"expression": "umbraBehaviorFinished()"},
+                params={
+                    "expression": "umbraBehaviorFinished()",
+                    # returnByValue ensures we can return more complicated types like dicts
+                    "returnByValue": True,
+                },
             )
             try:
                 self._wait_for(
@@ -905,11 +912,18 @@ class Browser:
                         "wasThrown" in msg["result"] and msg["result"]["wasThrown"]
                     )
                     and "result" in msg["result"]
-                    and isinstance(msg["result"]["result"]["value"], bool)
-                    and msg["result"]["result"]["value"]
                 ):
-                    self.logger.info("behavior decided it has finished")
-                    return
+                    if isinstance(msg["result"]["result"]["value"], bool):
+                        if msg["result"]["result"]["value"]:
+                            self.logger.info("behavior decided it has finished")
+                            return frozenset()
+                    # new-style response dict that has more than just a finished bool
+                    elif isinstance(msg["result"]["result"]["value"], dict):
+                        response = msg["result"]["result"]["value"]
+                        if response["finished"]:
+                            self.logger.info("behavior decided it has finished")
+                            outlinks = frozenset(response.get("outlinks", []))
+                            return outlinks
             except BrowsingTimeout:
                 pass