From d2831ab70901de885e57a084581b916c86a56bf6 Mon Sep 17 00:00:00 2001
From: ege-arhan <egearhany@gmail.com>
Date: Fri, 25 Sep 2026 06:04:11 +0000
Subject: [PATCH] fix(utils): pass allowed_tools tool_choice through to
 providers

Chat completions rejected the allowed_tools shape before it reached the provider, even though OpenAI accepts it. Keep the nested payload intact.
---
 litellm/utils.py                              |  6 ++++++
 .../test_validate_tool_choice.py              | 19 +++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/litellm/utils.py b/litellm/utils.py
index 4ea0769ea11..b751b9c0e1d 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -8328,6 +8328,12 @@ def validate_chat_completion_tool_choice(
         if tool_choice_type in ("auto", "none", "required") and "function" not in tool_choice:
             return tool_choice_type
 
+        # OpenAI also allows constraining which tools the model may call:
+        # {"type": "allowed_tools", "allowed_tools": {"mode": ..., "tools": [...]}}.
+        # Pass it through untouched so downstream providers see the full payload.
+        if tool_choice_type == "allowed_tools" and isinstance(tool_choice.get("allowed_tools"), dict):
+            return tool_choice
+
         # Standard OpenAI format: {"type": "function", "function": {...}}
         if tool_choice.get("type") is None or tool_choice.get("function") is None:
             raise BadRequestError(
diff --git a/tests/litellm_utils_tests/test_validate_tool_choice.py b/tests/litellm_utils_tests/test_validate_tool_choice.py
index a9dacf9fa15..a28aee87c48 100644
--- a/tests/litellm_utils_tests/test_validate_tool_choice.py
+++ b/tests/litellm_utils_tests/test_validate_tool_choice.py
@@ -36,6 +36,25 @@ def test_validate_tool_choice_cursor_format():
     assert validate_chat_completion_tool_choice({"type": "required"}, model=MODEL) == "required"
 
 
+def test_validate_tool_choice_allowed_tools_passthrough():
+    """Chat completions accepts the allowed_tools shape and keeps its payload intact."""
+    tool_choice = {
+        "type": "allowed_tools",
+        "allowed_tools": {
+            "mode": "required",
+            "tools": [{"type": "function", "function": {"name": "get_time"}}],
+        },
+    }
+    assert validate_chat_completion_tool_choice(tool_choice, model=MODEL) is tool_choice
+
+
+def test_validate_tool_choice_allowed_tools_without_payload_is_a_400():
+    """allowed_tools without its nested object stays a caller error."""
+    tool_choice = {"type": "allowed_tools"}
+    with pytest.raises(litellm.BadRequestError, match="Invalid tool choice"):
+        validate_chat_completion_tool_choice(tool_choice, model=MODEL)
+
+
 @pytest.mark.parametrize(
     "tool_choice",
     [