diff --git a/superset/mcp_service/chart/tool/update_chart_preview.py b/superset/mcp_service/chart/tool/update_chart_preview.py
index 4adcdad93af..e30d9690186 100644
--- a/superset/mcp_service/chart/tool/update_chart_preview.py
+++ b/superset/mcp_service/chart/tool/update_chart_preview.py
@@ -39,10 +39,32 @@ from superset.mcp_service.chart.schemas import (
     PerformanceMetadata,
     UpdateChartPreviewRequest,
 )
+from superset.utils import json as utils_json
 
 logger = logging.getLogger(__name__)
 
 
+def _get_old_adhoc_filters(form_data_key: str) -> list[Dict[str, Any]] | None:
+    """Retrieve adhoc_filters from the previously cached form_data."""
+    from superset.commands.exceptions import CommandException
+    from superset.commands.explore.form_data.get import GetFormDataCommand
+    from superset.commands.explore.form_data.parameters import CommandParameters
+
+    try:
+        cmd_params = CommandParameters(key=form_data_key)
+        cached_data = GetFormDataCommand(cmd_params).run()
+        if cached_data:
+            if isinstance(cached_data, str):
+                cached_data = utils_json.loads(cached_data)
+            if isinstance(cached_data, dict):
+                adhoc_filters = cached_data.get("adhoc_filters")
+                if adhoc_filters:
+                    return adhoc_filters
+    except (KeyError, ValueError, TypeError, CommandException):
+        logger.debug("Could not retrieve old form_data for filter preservation")
+    return None
+
+
 @tool(
     tags=["mutate"],
     class_permission_name="Chart",
@@ -81,6 +103,16 @@ def update_chart_preview(
             )
             new_form_data.pop("_mcp_warnings", None)
 
+            # Preserve adhoc filters from the previous cached form_data
+            # when the new config doesn't explicitly specify filters
+            if (
+                getattr(request.config, "filters", None) is None
+                and request.form_data_key
+            ):
+                old_adhoc_filters = _get_old_adhoc_filters(request.form_data_key)
+                if old_adhoc_filters:
+                    new_form_data["adhoc_filters"] = old_adhoc_filters
+
             # Generate new explore link with updated form_data
             explore_url = generate_explore_link(request.dataset_id, new_form_data)
 
diff --git a/superset/mcp_service/dashboard/schemas.py b/superset/mcp_service/dashboard/schemas.py
index be2860e07cb..67bf5397d79 100644
--- a/superset/mcp_service/dashboard/schemas.py
+++ b/superset/mcp_service/dashboard/schemas.py
@@ -566,8 +566,9 @@ def serialize_dashboard_object(dashboard: Any) -> DashboardInfo:
         else None,
         chart_count=len(getattr(dashboard, "slices", [])),
         owners=[
-            UserInfo.model_validate(owner, from_attributes=True)
+            info
             for owner in getattr(dashboard, "owners", [])
+            if (info := serialize_user_object(owner)) is not None
         ]
         if getattr(dashboard, "owners", None)
         else [],