[Bug] show_dashboard silently downgrades on_error="raise" to "store"

ConcurrentWorkflow documents on_error="raise" as "propagates the
exception and aborts the run". _run honours that. run_with_dashboard,
which run() dispatches to whenever show_dashboard=True, catches every
agent exception unconditionally and records it as that agent's output.

So the failure policy quietly depends on whether the dashboard happens
to be switched on. A caller who sets on_error="raise" to make agent
failures loud gets them swallowed instead, and the run returns a
conversation with "Error: ..." where an agent result should be.

Mirror the _run branch: re-raise when on_error == "raise", and route
the swallowed case through capture_error so the dashboard path stops
losing that telemetry too.

Author: ayaangazali

swarms/structs/concurrent_workflow.py

@@ -410,6 +410,16 @@ def agent_streaming_callback(chunk: str):
                         output = future.result()
                         results.append((agent.agent_name, output))
                     except Exception as e:
+                        if self.on_error == "raise":
+                            raise
+                        # Track the swallowed per-agent failure so it
+                        # isn't lost, same as the non-dashboard path.
+                        capture_error(
+                            e,
+                            self,
+                            name="ConcurrentWorkflow.agent_error",
+                            agent=getattr(agent, "agent_name", None),
+                        )
                         logger.error(
                             f"Agent {agent.agent_name} failed: {str(e)}"
                         )

tests/structs/test_concurrent_workflow.py

@@ -490,5 +490,53 @@ def test_concurrent_workflow_autosave_saves_conversation_after_run(
     get_workspace_dir.cache_clear()
 
 
+class _ExplodingAgent:
+    """Minimal agent stand-in whose run() always raises."""
+
+    def __init__(self, agent_name: str):
+        self.agent_name = agent_name
+        self.print_on = True
+
+    def run(self, *args, **kwargs):
+        raise RuntimeError("agent exploded")
+
+
+def test_dashboard_path_honors_on_error_raise(monkeypatch):
+    """show_dashboard must not downgrade on_error='raise'.
+
+    The dashboard path used to swallow every agent exception, so the
+    documented "propagates the exception and aborts the run" policy
+    only held while the dashboard was switched off.
+    """
+    workflow = ConcurrentWorkflow(
+        name="On-Error-Raise-Dashboard",
+        agents=[_ExplodingAgent("Boom")],
+        show_dashboard=True,
+        on_error="raise",
+    )
+    monkeypatch.setattr(
+        workflow, "display_agent_dashboard", lambda *a, **k: None
+    )
+
+    with pytest.raises(RuntimeError, match="agent exploded"):
+        workflow.run("anything")
+
+
+def test_dashboard_path_stores_errors_by_default(monkeypatch):
+    """on_error='store' still lets the run finish and records the error."""
+    workflow = ConcurrentWorkflow(
+        name="On-Error-Store-Dashboard",
+        agents=[_ExplodingAgent("Boom")],
+        show_dashboard=True,
+    )
+    monkeypatch.setattr(
+        workflow, "display_agent_dashboard", lambda *a, **k: None
+    )
+
+    workflow.run("anything")
+
+    assert "agent exploded" in workflow.conversation.get_str()
+
+
 if __name__ == "__main__":
     pytest.main([__file__, "-v"])