fix: DeepSeek-V3.x tool calling on ChatBedrockConverse

libs/aws/langchain_aws/chat_models/bedrock_converse.py

@@ -779,6 +779,11 @@ def validate_environment(self) -> Self:
                 self.supports_tool_choice_values = ("auto", "any")
             elif "nova" in base_model:
                 self.supports_tool_choice_values = ("auto", "any", "tool")
+            elif "deepseek" in base_model and "r1-v1" not in base_model:
+                if "v3-v1" in base_model:
+                    self.supports_tool_choice_values = ("any",)
+                else:
+                    self.supports_tool_choice_values = ("any", "tool")
             else:
                 self.supports_tool_choice_values = ()
 
@@ -1029,6 +1034,8 @@ def bind_tools(
                     f"for the latest documentation on models that support tool choice."
                 )
             kwargs["tool_choice"] = _format_tool_choice(tool_choice)
+        elif "deepseek.v3" in self._get_base_model():
+            kwargs["tool_choice"] = _format_tool_choice("any")
 
         return self.bind(tools=formatted_tools, **kwargs)
 

libs/aws/tests/unit_tests/chat_models/test_bedrock_converse.py

@@ -2,7 +2,7 @@
 
 import base64
 import os
-from typing import Any, Dict, List, Tuple, Type, Union, cast
+from typing import Any, Dict, List, Literal, Tuple, Type, Union, cast
 from unittest import mock
 
 import pytest
@@ -198,6 +198,71 @@ def test_llama_bind_tools_tool_choice_variants(
             chat_model.bind_tools([GetWeather], tool_choice="GetWeather")
 
 
+@pytest.mark.parametrize(
+    "model,expected_values",
+    [
+        ("us.deepseek.r1-v1:0", ()),
+        ("deepseek.v3-v1:0", ("any",)),
+        (
+            "deepseek.v3-x:0",
+            (
+                "any",
+                "tool",
+            ),
+        ),
+    ],
+)
+def test_deepseek_supports_tool_choice_values(
+    model: str, expected_values: tuple[Literal["auto", "any", "tool"], ...]
+) -> None:
+    chat_model = ChatBedrockConverse(model=model, region_name="us-east-1")
+    assert chat_model.supports_tool_choice_values == expected_values
+
+
+def test_deepseek_r1_no_tool_choice_support() -> None:
+    chat_model = ChatBedrockConverse(model="deepseek.r1-v1:0", region_name="us-east-1")  # type: ignore[call-arg]
+
+    assert chat_model.supports_tool_choice_values == ()
+
+    with pytest.raises(ValueError):
+        chat_model.bind_tools([GetWeather], tool_choice="auto")
+
+    with pytest.raises(ValueError):
+        chat_model.bind_tools([GetWeather], tool_choice="any")
+
+    with pytest.raises(ValueError):
+        chat_model.bind_tools(
+            [GetWeather], tool_choice={"tool": {"name": "GetWeather"}}
+        )
+
+    with pytest.raises(ValueError):
+        chat_model.bind_tools([GetWeather], tool_choice="GetWeather")
+
+
+def test_deepseek_v3_bind_tools_tool_choice_variants() -> None:
+    chat_model = ChatBedrockConverse(model="deepseek.v3-v1:0", region_name="us-east-1")  # type: ignore[call-arg]
+
+    chat_model_with_tools = chat_model.bind_tools([GetWeather], tool_choice="any")
+    assert cast(RunnableBinding, chat_model_with_tools).kwargs["tool_choice"] == {
+        "any": {}
+    }
+
+    with pytest.raises(ValueError):
+        chat_model.bind_tools([GetWeather], tool_choice="auto")
+
+    with pytest.raises(ValueError):
+        chat_model.bind_tools([GetWeather], tool_choice="GetWeather")
+
+
+def test_deepseek_v3_bind_tools_default_tool_choice() -> None:
+    chat_model = ChatBedrockConverse(model="deepseek.v3-v1:0", region_name="us-east-1")  # type: ignore[call-arg]
+
+    chat_model_with_tools = chat_model.bind_tools([GetWeather])
+    assert cast(RunnableBinding, chat_model_with_tools).kwargs["tool_choice"] == {
+        "any": {}
+    }
+
+
 def test__messages_to_bedrock() -> None:
     messages = [
         SystemMessage(content="sys1"),