diff --git a/schema-types.ts b/schema-types.ts
index ce03029..e17346b 100644
--- a/schema-types.ts
+++ b/schema-types.ts
@@ -11,7 +11,8 @@ export type SimToCmMessage = {
 export type Message = RequestApprovalToAttack | AcaFuelLow | MissileToOwnshipDetected | AcaDefect | AcaHeadingToBase;
 
 export type BaseMessage<TKind extends string, TData extends object> = {
-  id: MessageId,
+  id: Uuid,
+  conversationId: Uuid,
   priority: Priority,
   kind: TKind,
   data: TData,
@@ -52,7 +53,7 @@ export type AcaHeadingToBase = BaseMessage<"AcaHeadingToBase", {
 /* utility types **********************************************************************************/
 
 export type Id = number & tags.Type<"uint64">;
-export type MessageId = string & tags.Format<"uuid">;
+export type Uuid = string & tags.Format<"uuid">;
 export type Priority = DiscreteRange<0, 10>;
 export type Range<From extends number, To extends number> = number & tags.Type<"float"> & tags.Minimum<From> & tags.Maximum<To>;
 export type DiscreteRange<From extends number, To extends number> = number & tags.Type<"int64"> & tags.Minimum<From> & tags.Maximum<To>;