diff --git a/packages/sds/src/message_channel/mem_local_history.ts b/packages/sds/src/message_channel/mem_local_history.ts
index 8f715a89e0..4042ee69c4 100644
--- a/packages/sds/src/message_channel/mem_local_history.ts
+++ b/packages/sds/src/message_channel/mem_local_history.ts
@@ -48,6 +48,11 @@ export interface ILocalHistory {
   ): number;
 }
 
+export interface MemLocalHistoryOptions {
+  storage?: ChannelId | PersistentStorage;
+  maxSize?: number;
+}
+
 export class MemLocalHistory implements ILocalHistory {
   private items: ContentMessage[] = [];
   private readonly storage?: PersistentStorage;
@@ -60,9 +65,7 @@ export class MemLocalHistory implements ILocalHistory {
    *   - storage: Optional persistent storage backend for message persistence or channelId to use with PersistentStorage.
    *   - maxSize: The maximum number of messages to store. Optional, defaults to DEFAULT_MAX_LENGTH.
    */
-  public constructor(
-    opts: { storage?: ChannelId | PersistentStorage; maxSize?: number } = {}
-  ) {
+  public constructor(opts: MemLocalHistoryOptions = {}) {
     const { storage, maxSize } = opts;
     this.maxSize = maxSize ?? DEFAULT_MAX_LENGTH;
     if (storage instanceof PersistentStorage) {
diff --git a/packages/sds/src/message_channel/message_channel.spec.ts b/packages/sds/src/message_channel/message_channel.spec.ts
index f66330c478..ed66f10abf 100644
--- a/packages/sds/src/message_channel/message_channel.spec.ts
+++ b/packages/sds/src/message_channel/message_channel.spec.ts
@@ -15,7 +15,8 @@ import {
 } from "./message.js";
 import {
   DEFAULT_BLOOM_FILTER_OPTIONS,
-  MessageChannel
+  MessageChannel,
+  MessageChannelOptions
 } from "./message_channel.js";
 
 const channelId = "test-channel";
@@ -30,12 +31,7 @@ const callback = (_message: Message): Promise<{ success: boolean }> => {
 const createTestChannel = (
   channelId: string,
   senderId: string,
-  options: {
-    causalHistorySize?: number;
-    possibleAcksThreshold?: number;
-    timeoutForLostMessagesMs?: number;
-    enableRepair?: boolean;
-  } = {}
+  options: MessageChannelOptions = {}
 ): MessageChannel => {
   return new MessageChannel(
     channelId,