diff --git a/schema-types.ts b/schema-types.ts
index f189a9c..8040bdf 100644
--- a/schema-types.ts
+++ b/schema-types.ts
@@ -51,7 +51,7 @@ export type AcaHeadingToBase = BaseMessage<"AcaHeadingToBase", {
 
 /* utility types **********************************************************************************/
 
-export type Id = string;
+export type Id = string & tags.Format<"uuid">; 
 export type Priority = number & tags.Type<"uint32"> & tags.Maximum<10>;
 export type Range<From extends number, To extends number> = number & tags.Type<"float"> & tags.Minimum<From> & tags.Maximum<To>;