[Bugfix][Frontend] Convert Anthropic tool references to text

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Signed-off-by: Sai Sashankh D <530713+sashankh@users.noreply.github.com>

Author: sashankh

tests/entrypoints/anthropic/test_anthropic_messages_conversion.py

@@ -48,6 +48,8 @@
     validation_exception_handler,
 )
 
+pytestmark = pytest.mark.skip_global_cleanup
+
 _convert = AnthropicServingMessages._convert_anthropic_to_openai_request
 _img_url = AnthropicServingMessages._convert_image_source_to_url
 
@@ -238,6 +240,20 @@ def test_tool_result_text_blocks(self):
         assert len(tool_msg) == 1
         assert tool_msg[0]["content"] == "line 1\nline 2"
 
+    def test_tool_result_with_tool_reference(self):
+        request = self._make_tool_result_request(
+            [
+                {"type": "tool_reference", "tool_name": "list_files"},
+            ]
+        )
+        result = _convert(request)
+
+        tool_msg = [m for m in result.messages if m["role"] == "tool"]
+        assert len(tool_msg) == 2
+        assert tool_msg[1]["content"] == [
+            {"type": "text", "text": "[tool reference: list_files]"}
+        ]
+
     def test_tool_result_with_image(self):
         """Image in tool_result should produce a follow-up user message."""
         request = self._make_tool_result_request(

vllm/entrypoints/anthropic/serving.py

@@ -431,7 +431,10 @@ def _convert_user_tool_result(
                     ref_name = item.get("tool_name") or item.get("name")
                     if ref_name:
                         tool_reference.append(
-                            {"type": "tool_reference", "name": ref_name}
+                            {
+                                "type": "text",
+                                "text": f"[tool reference: {ref_name}]",
+                            }
                         )
             tool_text = "\n".join(text_parts)