diff --git a/src/model/openapi31.ts b/src/model/openapi31.ts
index 54e44d0..cff390c 100644
--- a/src/model/openapi31.ts
+++ b/src/model/openapi31.ts
@@ -301,6 +301,7 @@ export interface SchemaObject extends ISpecificationExtension {
     title?: string;
     multipleOf?: number;
     maximum?: number;
+    const?: string;
     /** @desc In OpenAPI 3.1: number */
     exclusiveMaximum?: number;
     minimum?: number;