From 289ac3f1a4366c7bba0a82239d4450ec547bdbeb Mon Sep 17 00:00:00 2001
From: VANDRANKI <prabhukiranvandranki@gmail.com>
Date: Wed, 30 Sep 2026 12:39:40 -0400
Subject: [PATCH 1/2] Python: keep a streamed '{}' delta when combining
 function call arguments

---
 .../contents/function_call_content.py         | 18 ++++++++++++-
 .../contents/test_function_call_content.py    | 26 +++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/python/semantic_kernel/contents/function_call_content.py b/python/semantic_kernel/contents/function_call_content.py
index e4ca2338111b..7a1d8cbec535 100644
--- a/python/semantic_kernel/contents/function_call_content.py
+++ b/python/semantic_kernel/contents/function_call_content.py
@@ -28,7 +28,7 @@
 
 _T = TypeVar("_T", bound="FunctionCallContent")
 
-EMPTY_VALUES: Final[list[str | None]] = ["", "{}", None]
+EMPTY_VALUES: Final[list[str | None]] = ["", None]
 
 
 class FunctionCallContent(KernelContent):
@@ -146,8 +146,24 @@ def combine_arguments(
             return arg2 or "{}"
         if arg2 in EMPTY_VALUES:
             return arg1 or "{}"
+        # A literal "{}" is only a placeholder when it stands next to a complete value. As the accumulated
+        # first side it is a finished empty object, so anything that follows replaces it. As the second side
+        # it is dropped only when the first side already parses as a complete object, otherwise it is a real
+        # delta (for example the value of a nested key) and must be kept.
+        if arg1 == "{}":
+            return arg2 or "{}"
+        if arg2 == "{}" and self._is_complete_object(arg1):
+            return arg1 or "{}"
         return (arg1 or "") + (arg2 or "")
 
+    @staticmethod
+    def _is_complete_object(value: str | None) -> bool:
+        """Check if the value is a complete JSON object."""
+        try:
+            return isinstance(json.loads(value or ""), Mapping)
+        except json.JSONDecodeError:
+            return False
+
     def parse_arguments(self) -> Mapping[str, Any] | None:
         """Parse the arguments into a dictionary."""
         if not self.arguments:
diff --git a/python/tests/unit/contents/test_function_call_content.py b/python/tests/unit/contents/test_function_call_content.py
index 6cdfc4557e99..5278096a3375 100644
--- a/python/tests/unit/contents/test_function_call_content.py
+++ b/python/tests/unit/contents/test_function_call_content.py
@@ -1,5 +1,7 @@
 # Copyright (c) Microsoft. All rights reserved.
 
+from functools import reduce
+
 import pytest
 
 from semantic_kernel.contents.function_call_content import FunctionCallContent
@@ -74,6 +76,30 @@ def test_add_empty():
     assert fc3.arguments == """{"input2": "world2"}"""
 
 
+@pytest.mark.parametrize(
+    "deltas",
+    [
+        ['{"query":"x","filters":', "{}", "}"],
+        ['{"a":[', "{}", ",", "{}", "]}"],
+        ['{"a": {"b":', "{}", "}}"],
+    ],
+)
+def test_add_streamed_empty_object_delta_is_kept(deltas: list[str]):
+    fcs = [
+        FunctionCallContent(id="test1" if i == 0 else None, index=0, name="Test-Function", arguments=d)
+        for i, d in enumerate(deltas)
+    ]
+    result = reduce(lambda a, b: a + b, fcs)
+    assert result.arguments == "".join(deltas)
+    assert result.parse_arguments() is not None
+
+
+def test_add_trailing_empty_placeholder_after_complete_object():
+    fc1 = FunctionCallContent(id="test1", name="Test-Function", arguments="""{"input2": "world2"}""")
+    fc2 = FunctionCallContent(id="test1", name="Test-Function", arguments="{}")
+    assert (fc1 + fc2).arguments == """{"input2": "world2"}"""
+
+
 def test_add_none(function_call: FunctionCallContent):
     # Test adding two function calls with one being None
     fc2 = None

From 04878684697265bb910818276b63dbc177ea38b6 Mon Sep 17 00:00:00 2001
From: VANDRANKI <prabhukiranvandranki@gmail.com>
Date: Thu, 1 Oct 2026 13:01:22 -0400
Subject: [PATCH 2/2] Python: treat single-quoted complete objects as complete
 when dropping a trailing '{}' placeholder

---
 python/semantic_kernel/contents/function_call_content.py | 5 +++++
 python/tests/unit/contents/test_function_call_content.py | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/python/semantic_kernel/contents/function_call_content.py b/python/semantic_kernel/contents/function_call_content.py
index 7a1d8cbec535..506c47fc8573 100644
--- a/python/semantic_kernel/contents/function_call_content.py
+++ b/python/semantic_kernel/contents/function_call_content.py
@@ -161,6 +161,11 @@ def _is_complete_object(value: str | None) -> bool:
         """Check if the value is a complete JSON object."""
         try:
             return isinstance(json.loads(value or ""), Mapping)
+        except json.JSONDecodeError:
+            pass
+        try:
+            # Same single quote preprocessing as parse_arguments.
+            return isinstance(json.loads(re.sub(r"(?<!\\)'", '"', value or "").replace("\\'", "'")), Mapping)
         except json.JSONDecodeError:
             return False
 
diff --git a/python/tests/unit/contents/test_function_call_content.py b/python/tests/unit/contents/test_function_call_content.py
index 5278096a3375..20575d411b9b 100644
--- a/python/tests/unit/contents/test_function_call_content.py
+++ b/python/tests/unit/contents/test_function_call_content.py
@@ -236,3 +236,11 @@ def test_fc_dump_json(function_call: FunctionCallContent):
         dumped
         == """{"metadata":{},"content_type":"function_call","id":"test","name":"Test-Function","function_name":"Function","plugin_name":"Test","arguments":"{\\"input\\": \\"world\\"}"}"""  # noqa: E501
     )
+
+
+def test_add_trailing_empty_placeholder_after_single_quoted_object():
+    fc1 = FunctionCallContent(id="test1", name="Test-Function", arguments="{'input': 'world'}")
+    fc2 = FunctionCallContent(id="test1", name="Test-Function", arguments="{}")
+    result = fc1 + fc2
+    assert result.arguments == "{'input': 'world'}"
+    assert result.parse_arguments() == {"input": "world"}