fix(bedrock): fall back to sync calls from acall

lib/crewai/src/crewai/llms/providers/bedrock/completion.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import asyncio
 from collections.abc import Mapping, Sequence
 from contextlib import AsyncExitStack
 import json
@@ -485,15 +486,25 @@ class BedrockCompletion(BaseLLM):
             Generated text response or structured output.
 
         Raises:
-            NotImplementedError: If aiobotocore is not installed.
             LLMContextLengthExceededError: If context window is exceeded.
         """
         effective_response_model = response_model or self.response_format
 
         if not AIOBOTOCORE_AVAILABLE:
-            raise NotImplementedError(
-                "Async support for AWS Bedrock requires aiobotocore. "
-                'Install with: uv add "crewai[bedrock]"'
+            logging.warning(
+                "aiobotocore is not installed; falling back to synchronous AWS "
+                "Bedrock calls in a worker thread. Install `crewai[bedrock]` "
+                "for native async support."
+            )
+            return await asyncio.to_thread(
+                self.call,
+                messages,
+                tools=tools,
+                callbacks=callbacks,
+                available_functions=available_functions,
+                from_task=from_task,
+                from_agent=from_agent,
+                response_model=effective_response_model,
             )
 
         with llm_call_context():

lib/crewai/tests/llms/bedrock/test_bedrock.py

@@ -1,4 +1,6 @@
+import logging
 import os
+import threading
 from unittest.mock import patch, MagicMock
 import pytest
 
@@ -210,6 +212,45 @@ def test_bedrock_completion_call():
         mock_call.assert_called_once_with("Hello, how are you?")
 
 
+@pytest.mark.asyncio
+async def test_bedrock_acall_falls_back_to_sync_call_without_aiobotocore(caplog):
+    """Async Bedrock calls remain usable when only the sync SDK is installed."""
+    llm = LLM(model="bedrock/anthropic.claude-3-5-sonnet-20241022-v2:0")
+    callbacks = [MagicMock()]
+    available_functions = {"lookup": MagicMock()}
+    call_thread_id: int | None = None
+
+    def sync_call(*args, **kwargs):
+        nonlocal call_thread_id
+        call_thread_id = threading.get_ident()
+        return "fallback response"
+
+    with caplog.at_level(logging.WARNING):
+        with (
+            patch.object(bedrock_completion, "AIOBOTOCORE_AVAILABLE", False),
+            patch.object(llm, "call", side_effect=sync_call) as mock_call,
+        ):
+            event_loop_thread_id = threading.get_ident()
+            result = await llm.acall(
+                "Hello, how are you?",
+                callbacks=callbacks,
+                available_functions=available_functions,
+            )
+
+    assert result == "fallback response"
+    assert call_thread_id != event_loop_thread_id
+    assert "falling back to synchronous AWS Bedrock calls" in caplog.text
+    mock_call.assert_called_once_with(
+        "Hello, how are you?",
+        tools=None,
+        callbacks=callbacks,
+        available_functions=available_functions,
+        from_task=None,
+        from_agent=None,
+        response_model=None,
+    )
+
+
 def test_bedrock_completion_called_during_crew_execution():
     """
     Test that BedrockCompletion.call is actually invoked when running a crew