From 544a0be65b3f24ebf01538ac4e5a3b1ad6c8f1d0 Mon Sep 17 00:00:00 2001
From: Luis Rodriguez <luis.rodriguez@bcpos.com>
Date: Tue, 18 Aug 2026 10:05:04 -0400
Subject: [PATCH] fix: include arguments for zero-argument eval tool calls

---
 .../core/agent_framework/_evaluation.py       |  3 +--
 .../foundry/tests/test_foundry_evals.py       | 20 +++++++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/python/packages/core/agent_framework/_evaluation.py b/python/packages/core/agent_framework/_evaluation.py
index cac000ca0b2..326e44032be 100644
--- a/python/packages/core/agent_framework/_evaluation.py
+++ b/python/packages/core/agent_framework/_evaluation.py
@@ -796,9 +796,8 @@ def convert_message(message: Message) -> list[dict[str, Any]]:
                     "type": "tool_call",
                     "tool_call_id": c.call_id or "",
                     "name": c.name or "",
+                    "arguments": args if args is not None else {},
                 }
-                if args:
-                    tc["arguments"] = args
                 content_items.append(tc)
             elif c.type == "function_result":
                 result_val = c.result
diff --git a/python/packages/foundry/tests/test_foundry_evals.py b/python/packages/foundry/tests/test_foundry_evals.py
index 575a5976bbf..636593b47a2 100644
--- a/python/packages/foundry/tests/test_foundry_evals.py
+++ b/python/packages/foundry/tests/test_foundry_evals.py
@@ -153,6 +153,26 @@ def test_assistant_with_tool_call(self) -> None:
         assert tc["name"] == "get_weather"
         assert tc["arguments"] == {"location": "Seattle"}
 
+    def test_assistant_with_zero_argument_tool_call(self) -> None:
+        msg = Message(
+            "assistant",
+            [Content.from_function_call(call_id="call_1", name="get_site_summary", arguments=None)],
+        )
+
+        result = AgentEvalConverter.convert_message(msg)
+
+        assert result[0]["content"][0]["arguments"] == {}
+
+    def test_assistant_with_empty_argument_object_tool_call(self) -> None:
+        msg = Message(
+            "assistant",
+            [Content.from_function_call(call_id="call_1", name="get_site_summary", arguments={})],
+        )
+
+        result = AgentEvalConverter.convert_message(msg)
+
+        assert result[0]["content"][0]["arguments"] == {}
+
     def test_assistant_text_and_tool_call(self) -> None:
         msg = Message(
             "assistant",