From a0cef91f0b355e659c3a11756f344d070f2324ae Mon Sep 17 00:00:00 2001
From: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Date: Wed, 30 Sep 2026 18:50:14 -0700
Subject: [PATCH] fix(bedrock): forward a non-string reasoning_effort on the
 native route instead of crashing

A list or dict reasoning_effort hit a frozenset membership test in
without_refused_reasoning_effort and raised TypeError, which the proxy
surfaced as a 500 APIConnectionError with no upstream call. The value is
now left alone unless it is a string Bedrock's native endpoint refuses,
so AWS answers the malformed value with its own 400 like it does for an int
---
 .../bedrock/chat/chat_completions/transformation.py |  3 ++-
 .../test_bedrock_chat_completions_transformation.py | 13 +++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/litellm/llms/bedrock/chat/chat_completions/transformation.py b/litellm/llms/bedrock/chat/chat_completions/transformation.py
index 1477a46dcad..ac1d2cf2498 100644
--- a/litellm/llms/bedrock/chat/chat_completions/transformation.py
+++ b/litellm/llms/bedrock/chat/chat_completions/transformation.py
@@ -108,7 +108,8 @@ def chat_completions_reasoning_efforts_refused_for(model: str) -> frozenset[str]
 
 
 def without_refused_reasoning_effort(model: str, params: Mapping[str, object]) -> Mapping[str, object]:
-    if params.get("reasoning_effort") not in chat_completions_reasoning_efforts_refused_for(model):
+    effort: Final = params.get("reasoning_effort")
+    if not isinstance(effort, str) or effort not in chat_completions_reasoning_efforts_refused_for(model):
         return params
     return _without_params(params, frozenset(("reasoning_effort",)))
 
diff --git a/tests/unit/llms/bedrock/chat/chat_completions/test_bedrock_chat_completions_transformation.py b/tests/unit/llms/bedrock/chat/chat_completions/test_bedrock_chat_completions_transformation.py
index 5ea3c8c31bd..db1efd49cb9 100644
--- a/tests/unit/llms/bedrock/chat/chat_completions/test_bedrock_chat_completions_transformation.py
+++ b/tests/unit/llms/bedrock/chat/chat_completions/test_bedrock_chat_completions_transformation.py
@@ -573,6 +573,19 @@ def test_map_openai_params_keeps_reasoning_effort_low_for_grok():
     assert mapped["reasoning_effort"] == "low"
 
 
+@pytest.mark.parametrize("model", ["us.xai.grok-4.6", "global.openai.gpt-5.6-sol"])
+@pytest.mark.parametrize("reasoning_effort", [["low"], {"effort": "low"}, 5])
+def test_map_openai_params_forwards_a_malformed_reasoning_effort_for_aws_to_refuse(model, reasoning_effort):
+    cfg = AmazonBedrockRuntimeChatCompletionsConfig()
+    mapped = cfg.map_openai_params(
+        non_default_params={"reasoning_effort": reasoning_effort, "max_tokens": 64},
+        optional_params={},
+        model=model,
+        drop_params=False,
+    )
+    assert mapped["reasoning_effort"] == reasoning_effort
+
+
 def test_map_openai_params_keeps_reasoning_effort_none_for_gpt56():
     cfg = AmazonBedrockRuntimeChatCompletionsConfig()
     mapped = cfg.map_openai_params(