diff --git a/python/packages/bedrock/agent_framework_bedrock/_chat_client.py b/python/packages/bedrock/agent_framework_bedrock/_chat_client.py
index 3606cdf26b..bcd04de0f7 100644
--- a/python/packages/bedrock/agent_framework_bedrock/_chat_client.py
+++ b/python/packages/bedrock/agent_framework_bedrock/_chat_client.py
@@ -411,14 +411,14 @@ def _prepare_options(
                     # Omit toolConfig entirely so the model won't attempt tool calls.
                     tool_config = None
                 case "auto":
-                    tool_config = tool_config or {}
-                    tool_config["toolChoice"] = {"auto": {}}
+                    if tool_config and "tools" in tool_config:
+                        tool_config["toolChoice"] = {"auto": {}}
                 case "required":
-                    tool_config = tool_config or {}
-                    if required_name := tool_mode.get("required_function_name"):
-                        tool_config["toolChoice"] = {"tool": {"name": required_name}}
-                    else:
-                        tool_config["toolChoice"] = {"any": {}}
+                    if tool_config and "tools" in tool_config:
+                        if required_name := tool_mode.get("required_function_name"):
+                            tool_config["toolChoice"] = {"tool": {"name": required_name}}
+                        else:
+                            tool_config["toolChoice"] = {"any": {}}
                 case _:
                     raise ValueError(f"Unsupported tool mode for Bedrock: {tool_mode.get('mode')}")
         if tool_config:
diff --git a/python/packages/bedrock/tests/test_bedrock_client.py b/python/packages/bedrock/tests/test_bedrock_client.py
index fbc241b24c..959f5bf5c5 100644
--- a/python/packages/bedrock/tests/test_bedrock_client.py
+++ b/python/packages/bedrock/tests/test_bedrock_client.py
@@ -137,3 +137,39 @@ def test_prepare_options_tool_choice_required_includes_any() -> None:
 
     assert "toolConfig" in request
     assert request["toolConfig"]["toolChoice"] == {"any": {}}
+
+
+
+def test_prepare_options_tool_choice_auto_without_tools_omits_tool_config() -> None:
+    """When tool_choice='auto' but no tools are provided, toolConfig must be omitted.
+
+    Without tools, setting toolChoice would cause a ParamValidationError from Bedrock.
+    """
+    client = _make_client()
+    messages = [Message(role="user", contents=[Content.from_text(text="hello")])]
+
+    options: dict[str, Any] = {
+        "tool_choice": "auto",
+    }
+
+    request = client._prepare_options(messages, options)
+
+    assert "toolConfig" not in request, (
+        f"toolConfig should be omitted when no tools are provided, got: {request.get('toolConfig')}"
+    )
+
+
+def test_prepare_options_tool_choice_required_without_tools_omits_tool_config() -> None:
+    """When tool_choice='required' but no tools are provided, toolConfig must be omitted."""
+    client = _make_client()
+    messages = [Message(role="user", contents=[Content.from_text(text="hello")])]
+
+    options: dict[str, Any] = {
+        "tool_choice": "required",
+    }
+
+    request = client._prepare_options(messages, options)
+
+    assert "toolConfig" not in request, (
+        f"toolConfig should be omitted when no tools are provided, got: {request.get('toolConfig')}"
+    )
diff --git a/test_addition.py b/test_addition.py
new file mode 100644
index 0000000000..ae493672bc
--- /dev/null
+++ b/test_addition.py
@@ -0,0 +1,36 @@
+
+
+
+def test_prepare_options_tool_choice_auto_without_tools_omits_tool_config() -> None:
+    """When tool_choice='auto' but no tools are provided, toolConfig must be omitted.
+
+    Without tools, setting toolChoice would cause a ParamValidationError from Bedrock.
+    """
+    client = _make_client()
+    messages = [Message(role="user", contents=[Content.from_text(text="hello")])]
+
+    options: dict[str, Any] = {
+        "tool_choice": "auto",
+    }
+
+    request = client._prepare_options(messages, options)
+
+    assert "toolConfig" not in request, (
+        f"toolConfig should be omitted when no tools are provided, got: {request.get('toolConfig')}"
+    )
+
+
+def test_prepare_options_tool_choice_required_without_tools_omits_tool_config() -> None:
+    """When tool_choice='required' but no tools are provided, toolConfig must be omitted."""
+    client = _make_client()
+    messages = [Message(role="user", contents=[Content.from_text(text="hello")])]
+
+    options: dict[str, Any] = {
+        "tool_choice": "required",
+    }
+
+    request = client._prepare_options(messages, options)
+
+    assert "toolConfig" not in request, (
+        f"toolConfig should be omitted when no tools are provided, got: {request.get('toolConfig')}"
+    )