diff --git a/python/packages/core/agent_framework/_agents.py b/python/packages/core/agent_framework/_agents.py
index a3f4570b6e..c8ccf3c9e5 100644
--- a/python/packages/core/agent_framework/_agents.py
+++ b/python/packages/core/agent_framework/_agents.py
@@ -81,6 +81,14 @@
 )
 
 
+def _get_tool_name(tool: Any) -> str | None:
+    """Extract the name from a tool, supporting both objects and dicts."""
+    if isinstance(tool, dict):
+        name: str | None = tool.get("function", {}).get("name")
+        return name
+    return getattr(tool, "name", None)
+
+
 def _merge_options(base: dict[str, Any], override: dict[str, Any]) -> dict[str, Any]:
     """Merge two options dicts, with override values taking precedence.
 
@@ -97,8 +105,9 @@ def _merge_options(base: dict[str, Any], override: dict[str, Any]) -> dict[str,
             continue
         if key == "tools" and result.get("tools"):
             # Combine tool lists, avoiding duplicates by name
-            existing_names = {getattr(t, "name", None) for t in result["tools"]}
-            unique_new = [t for t in value if getattr(t, "name", None) not in existing_names]
+            existing_names = {_get_tool_name(t) for t in result["tools"]}
+            existing_names.discard(None)
+            unique_new = [t for t in value if _get_tool_name(t) not in existing_names]
             result["tools"] = list(result["tools"]) + unique_new
         elif key == "logit_bias" and result.get("logit_bias"):
             # Merge logit_bias dicts
diff --git a/python/packages/core/tests/core/test_agents.py b/python/packages/core/tests/core/test_agents.py
index 627987a1f2..d21fd6e7bb 100644
--- a/python/packages/core/tests/core/test_agents.py
+++ b/python/packages/core/tests/core/test_agents.py
@@ -25,7 +25,7 @@
     SupportsChatGetResponse,
     tool,
 )
-from agent_framework._agents import _merge_options, _sanitize_agent_name
+from agent_framework._agents import _get_tool_name, _merge_options, _sanitize_agent_name
 from agent_framework._mcp import MCPTool
 
 
@@ -880,6 +880,71 @@ def __init__(self, name):
     assert "tool2" in tool_names
 
 
+def test_merge_options_dict_tools_combined():
+    """Test _merge_options combines dict-defined tool lists without dropping tools."""
+    base = {
+        "tools": [
+            {"type": "function", "function": {"name": "tool_a"}},
+        ]
+    }
+    override = {
+        "tools": [
+            {"type": "function", "function": {"name": "tool_b"}},
+        ]
+    }
+
+    result = _merge_options(base, override)
+
+    assert len(result["tools"]) == 2
+    names = [_get_tool_name(t) for t in result["tools"]]
+    assert "tool_a" in names
+    assert "tool_b" in names
+
+
+def test_merge_options_dict_tools_deduplicates():
+    """Test _merge_options deduplicates dict-defined tools by function name."""
+    base = {
+        "tools": [
+            {"type": "function", "function": {"name": "tool_a"}},
+        ]
+    }
+    override = {
+        "tools": [
+            {"type": "function", "function": {"name": "tool_a"}},
+            {"type": "function", "function": {"name": "tool_b"}},
+        ]
+    }
+
+    result = _merge_options(base, override)
+
+    assert len(result["tools"]) == 2
+    names = [_get_tool_name(t) for t in result["tools"]]
+    assert names.count("tool_a") == 1
+    assert "tool_b" in names
+
+
+def test_get_tool_name_dict():
+    """Test _get_tool_name extracts name from dict-defined tools."""
+    tool = {"type": "function", "function": {"name": "my_tool"}}
+    assert _get_tool_name(tool) == "my_tool"
+
+
+def test_get_tool_name_object():
+    """Test _get_tool_name extracts name from object-defined tools."""
+
+    class MockTool:
+        def __init__(self, name):
+            self.name = name
+
+    assert _get_tool_name(MockTool("my_tool")) == "my_tool"
+
+
+def test_get_tool_name_no_name():
+    """Test _get_tool_name returns None when no name is available."""
+    assert _get_tool_name({}) is None
+    assert _get_tool_name(42) is None
+
+
 def test_merge_options_logit_bias_merged():
     """Test _merge_options merges logit_bias dicts."""
     base = {"logit_bias": {"token1": 1.0}}