diff --git a/proposals/predict_curve.json b/proposals/predict_curve.json
index 479b7fec..62bc1660 100644
--- a/proposals/predict_curve.json
+++ b/proposals/predict_curve.json
@@ -59,13 +59,8 @@
         },
         {
             "name": "labels",
-            "description": "The labels to predict values for. If no labels are given, predicts values only for no-data (`null`) values in the data cube.",
-            "optional": true,
-            "default": null,
+            "description": "The labels to predict values for.",
             "schema": [
-                {
-                    "type": "null"
-                },
                 {
                     "type": "array",
                     "items": {