diff --git a/packages/coreutils/src/token.ts b/packages/coreutils/src/token.ts
index 8e4e962d4..2ec309bc0 100644
--- a/packages/coreutils/src/token.ts
+++ b/packages/coreutils/src/token.ts
@@ -31,7 +31,7 @@ export class Token<T> {
   /**
    * Token purpose description.
    */
-  readonly description: string;
+  readonly description?: string; // FIXME remove `?` for the next major version
 
   /**
    * The human readable name for the token.
diff --git a/review/api/coreutils.api.md b/review/api/coreutils.api.md
index 8d8816b10..d8fcfa10c 100644
--- a/review/api/coreutils.api.md
+++ b/review/api/coreutils.api.md
@@ -109,7 +109,7 @@ export type ReadonlyPartialJSONValue = JSONPrimitive | ReadonlyPartialJSONObject
 // @public
 export class Token<T> {
     constructor(name: string, description?: string);
-    readonly description: string;
+    readonly description?: string;
     readonly name: string;
 }