From 18912921f6448cd7e034d8963bbfdfce98f301cb Mon Sep 17 00:00:00 2001
From: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Date: Sat, 4 Apr 2026 22:41:20 -0700
Subject: [PATCH] Python: Strip tools from FoundryAgent request when
 agent_reference is present

_prepare_options() now removes tools, tool_choice, and parallel_tool_calls
from run_options after injecting agent_reference. The Foundry API rejects
requests containing both fields. FunctionTools are still invoked client-side
by the function invocation layer.

Fixes #5087

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 .../foundry/agent_framework_foundry/_agent.py |  7 ++++
 .../tests/foundry/test_foundry_agent.py       | 39 +++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/python/packages/foundry/agent_framework_foundry/_agent.py b/python/packages/foundry/agent_framework_foundry/_agent.py
index a499abf6f4..bf5d936d9d 100644
--- a/python/packages/foundry/agent_framework_foundry/_agent.py
+++ b/python/packages/foundry/agent_framework_foundry/_agent.py
@@ -293,6 +293,13 @@ async def _prepare_options(
         # Inject agent reference
         run_options["extra_body"] = {"agent_reference": self._get_agent_reference()}
 
+        # Strip tools from request body - Foundry API rejects requests with both
+        # agent_reference and tools present. FunctionTools are invoked client-side
+        # by the function invocation layer, not sent to the service.
+        run_options.pop("tools", None)
+        run_options.pop("tool_choice", None)
+        run_options.pop("parallel_tool_calls", None)
+
         return run_options
 
     @override
diff --git a/python/packages/foundry/tests/foundry/test_foundry_agent.py b/python/packages/foundry/tests/foundry/test_foundry_agent.py
index 09a31f941b..829af6ab87 100644
--- a/python/packages/foundry/tests/foundry/test_foundry_agent.py
+++ b/python/packages/foundry/tests/foundry/test_foundry_agent.py
@@ -200,6 +200,45 @@ def my_func() -> str:
     assert result["extra_body"]["agent_reference"]["name"] == "test-agent"
 
 
+async def test_raw_foundry_agent_chat_client_prepare_options_strips_tools() -> None:
+    """Test that _prepare_options strips tools, tool_choice, and parallel_tool_calls from run_options."""
+
+    mock_project = MagicMock()
+    mock_openai = MagicMock()
+    mock_project.get_openai_client.return_value = mock_openai
+
+    client = RawFoundryAgentChatClient(
+        project_client=mock_project,
+        agent_name="test-agent",
+    )
+
+    @tool(approval_mode="never_require")
+    def my_func() -> str:
+        """A test function."""
+
+        return "ok"
+
+    with patch(
+        "agent_framework_openai._chat_client.RawOpenAIChatClient._prepare_options",
+        new_callable=AsyncMock,
+        return_value={
+            "tools": [{"type": "function", "function": {"name": "my_func"}}],
+            "tool_choice": "auto",
+            "parallel_tool_calls": True,
+        },
+    ):
+        result = await client._prepare_options(
+            messages=[Message(role="user", contents="hi")],
+            options={"tools": [my_func]},
+        )
+
+    assert "tools" not in result
+    assert "tool_choice" not in result
+    assert "parallel_tool_calls" not in result
+    assert "extra_body" in result
+    assert result["extra_body"]["agent_reference"]["name"] == "test-agent"
+
+
 def test_raw_foundry_agent_chat_client_check_model_presence_is_noop() -> None:
     """Test that _check_model_presence does nothing (model is on service)."""