From 43fbac8bc5d1966e10c7370527c560f2a29ab21c Mon Sep 17 00:00:00 2001
From: Rachit Mehta <mehtarac@amazon.com>
Date: Mon, 11 May 2026 12:36:16 -0400
Subject: [PATCH 1/2] fix: swarm bug

---
 src/strands/multiagent/swarm.py | 27 +++++++++++----------------
 1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/src/strands/multiagent/swarm.py b/src/strands/multiagent/swarm.py
index f5731a371..1a2e9130a 100644
--- a/src/strands/multiagent/swarm.py
+++ b/src/strands/multiagent/swarm.py
@@ -17,6 +17,7 @@
 import copy
 import json
 import logging
+import sys
 import time
 from collections.abc import AsyncIterator, Callable, Mapping
 from dataclasses import dataclass, field
@@ -439,28 +440,22 @@ async def _stream_with_timeout(
             Exception: If total execution time exceeds timeout
         """
         if timeout is None:
-            # No timeout - just pass through
             async for event in async_generator:
                 yield event
+        elif sys.version_info >= (3, 11):
+            try:
+                async with asyncio.timeout(timeout):
+                    async for event in async_generator:
+                        yield event
+            except asyncio.TimeoutError as err:
+                raise Exception(timeout_message) from err
         else:
-            # Track start time for total timeout
             start_time = asyncio.get_event_loop().time()
-
-            while True:
-                # Calculate remaining time from total timeout budget
+            async for event in async_generator:
                 elapsed = asyncio.get_event_loop().time() - start_time
-                remaining = timeout - elapsed
-
-                if remaining <= 0:
+                if elapsed > timeout:
                     raise Exception(timeout_message)
-
-                try:
-                    event = await asyncio.wait_for(async_generator.__anext__(), timeout=remaining)
-                    yield event
-                except StopAsyncIteration:
-                    break
-                except asyncio.TimeoutError as err:
-                    raise Exception(timeout_message) from err
+                yield event
 
     def _setup_swarm(self, nodes: list[Agent]) -> None:
         """Initialize swarm configuration."""

From ca773039023999f66c87e2eb5cc5858443ec4c52 Mon Sep 17 00:00:00 2001
From: Rachit Mehta <mehtarac@amazon.com>
Date: Tue, 12 May 2026 08:49:00 -0400
Subject: [PATCH 2/2] address comments

---
 src/strands/multiagent/swarm.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/strands/multiagent/swarm.py b/src/strands/multiagent/swarm.py
index 1a2e9130a..b0f9f4a86 100644
--- a/src/strands/multiagent/swarm.py
+++ b/src/strands/multiagent/swarm.py
@@ -450,9 +450,12 @@ async def _stream_with_timeout(
             except asyncio.TimeoutError as err:
                 raise Exception(timeout_message) from err
         else:
-            start_time = asyncio.get_event_loop().time()
+            # Python 3.10 fallback: timeout is only checked between yielded events.
+            # A generator that hangs mid-await won't be interrupted until the next event.
+            # Remove once Python 3.10 support is dropped (Oct 2026).
+            start_time = asyncio.get_running_loop().time()
             async for event in async_generator:
-                elapsed = asyncio.get_event_loop().time() - start_time
+                elapsed = asyncio.get_running_loop().time() - start_time
                 if elapsed > timeout:
                     raise Exception(timeout_message)
                 yield event