diff --git a/frigate/api/chat.py b/frigate/api/chat.py
index 25fbbb9d42..e8de6b7fd3 100644
--- a/frigate/api/chat.py
+++ b/frigate/api/chat.py
@@ -542,9 +542,7 @@ async def execute_tool(
 
     if tool_name == "get_categorized_object_names":
         return JSONResponse(
-            content=_execute_get_categorized_object_names(
-                request, arguments, allowed_cameras
-            )
+            content=_execute_get_categorized_object_names(request, allowed_cameras)
         )
 
     if tool_name == "find_similar_objects":
@@ -727,22 +725,14 @@ async def _execute_set_camera_state(
 
 def _execute_get_categorized_object_names(
     request: Request,
-    arguments: dict[str, Any],
     allowed_cameras: list[str],
 ) -> dict[str, Any]:
-    object_type = arguments.get("object_type") or None
-    names = get_categorized_object_names(
-        request.app.frigate_config, allowed_cameras, object_type
-    )
+    names = get_categorized_object_names(request.app.frigate_config, allowed_cameras)
 
     if not names:
         return {
             "names": {},
-            "message": (
-                f"No names configured for '{object_type}'."
-                if object_type
-                else "No names configured; search by label or semantic_query."
-            ),
+            "message": "No names configured; search by label or semantic_query.",
         }
 
     return {"names": names}
@@ -773,9 +763,7 @@ async def _execute_tool_internal(
             logger.warning(f"Failed to extract tool result: {e}")
             return {"error": "Failed to parse tool result"}
     elif tool_name == "get_categorized_object_names":
-        return _execute_get_categorized_object_names(
-            request, arguments, allowed_cameras
-        )
+        return _execute_get_categorized_object_names(request, allowed_cameras)
     elif tool_name == "find_similar_objects":
         return await _execute_find_similar_objects(request, arguments, allowed_cameras)
     elif tool_name == "set_camera_state":
diff --git a/frigate/genai/prompts.py b/frigate/genai/prompts.py
index e350a43245..862b48fd4e 100644
--- a/frigate/genai/prompts.py
+++ b/frigate/genai/prompts.py
@@ -354,16 +354,12 @@ def get_tool_definitions(
                 "description": (
                     "Every name that can be attached as a sub_label, grouped by object "
                     "type: recognized faces, named license plates, classification "
-                    "categories, and delivery logos."
+                    "categories, and delivery logos. Takes no arguments and always "
+                    "returns the complete map."
                 ),
                 "parameters": {
                     "type": "object",
-                    "properties": {
-                        "object_type": {
-                            "type": "string",
-                            "description": "Optional object label (e.g. 'person', 'car'). Omit for all.",
-                        },
-                    },
+                    "properties": {},
                     "required": [],
                 },
             },