diff --git a/schemas/config.json b/schemas/config.json
index dcf62d9..c4ba8b3 100644
--- a/schemas/config.json
+++ b/schemas/config.json
@@ -162,8 +162,7 @@
           "type": "array",
           "items": {
             "$ref": "#/definitions/PredicateParameter"
-          },
-          "minItems": 1
+          }
         }
       }
     },
diff --git a/src/lib.rs b/src/lib.rs
index 5b9467d..d0657fe 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -211,7 +211,6 @@ pub struct Predicate {
     /// A short description of the predicate (in Markdown format).
     pub description: String,
     /// The list of valid parameter types.
-    #[cfg_attr(feature = "schema", schemars(length(min = 1)))]
     pub parameters: Vec<PredicateParameter>,
 }