diff --git a/src/claude_agent_sdk/_internal/query.py b/src/claude_agent_sdk/_internal/query.py
index 76460100..1f549c7c 100644
--- a/src/claude_agent_sdk/_internal/query.py
+++ b/src/claude_agent_sdk/_internal/query.py
@@ -233,14 +233,10 @@ async def _handle_control_request(self, request: SDKControlRequest) -> None:
 
                 # Convert PermissionResult to expected dict format
                 if isinstance(response, PermissionResultAllow):
-                    response_data = {
-                        "behavior": "allow",
-                        "updatedInput": (
-                            response.updated_input
-                            if response.updated_input is not None
-                            else original_input
-                        ),
-                    }
+                    response_data = {"behavior": "allow"}
+                    # Only include updatedInput if explicitly provided by the user
+                    if response.updated_input is not None:
+                        response_data["updatedInput"] = response.updated_input
                     if response.updated_permissions is not None:
                         response_data["updatedPermissions"] = [
                             permission.to_dict()
diff --git a/tests/test_tool_callbacks.py b/tests/test_tool_callbacks.py
index 8ace3c8d..7811406e 100644
--- a/tests/test_tool_callbacks.py
+++ b/tests/test_tool_callbacks.py
@@ -96,6 +96,13 @@ async def allow_callback(
         response = transport.written_messages[0]
         assert '"behavior": "allow"' in response
 
+        # IMPORTANT: Verify updatedInput is NOT included when not provided
+        # This is the regression test for issue #1063
+        assert '"updatedInput"' not in response, (
+            "updatedInput should not be included when PermissionResultAllow() "
+            "is returned without updated_input parameter"
+        )
+
     @pytest.mark.asyncio
     async def test_permission_callback_deny(self):
         """Test callback that denies tool execution."""