diff --git a/agents-api/agents_api/common/protocol/sessions.py b/agents-api/agents_api/common/protocol/sessions.py
index 1e98f7f12..a675a479f 100644
--- a/agents-api/agents_api/common/protocol/sessions.py
+++ b/agents-api/agents_api/common/protocol/sessions.py
@@ -94,9 +94,12 @@ def get_active_tools(self) -> list[Tool]:
         Get the active toolset from the session data.
         """
         active_agent = self.get_active_agent()
-        active_toolset = next(
-            toolset for toolset in self.toolsets if toolset.agent_id == active_agent.id
-        )
+        try:
+            active_toolset = next(
+                toolset for toolset in self.toolsets if toolset.agent_id == active_agent.id
+            )
+        except StopIteration:
+            return []
 
         return active_toolset.tools