diff --git a/types-tests/message.test-d.ts b/types-tests/message.test-d.ts
index f1eb598b8..bfcd10820 100644
--- a/types-tests/message.test-d.ts
+++ b/types-tests/message.test-d.ts
@@ -1,83 +1,98 @@
-import { expectNotType, expectType, expectError } from "tsd";
-import App from "../src/App";
-import type {
-  MessageEvent,
-  GenericMessageEvent,
-  BotMessageEvent,
-  MessageRepliedEvent,
-  MeMessageEvent,
-  MessageDeletedEvent,
-  ThreadBroadcastMessageEvent,
-  MessageChangedEvent,
-  EKMAccessDeniedMessageEvent,
-} from "..";
+import { expectNotType, expectType, expectError } from 'tsd';
+// eslint-disable-next-line
+import App from '../src/App';
+import {
+  type MessageEvent,
+  type GenericMessageEvent,
+  type BotMessageEvent,
+  type MessageRepliedEvent,
+  type MeMessageEvent,
+  type MessageDeletedEvent,
+  type ThreadBroadcastMessageEvent,
+  type MessageChangedEvent,
+  type EKMAccessDeniedMessageEvent,
+  AllMessageEvents,
+} from '..';
 
-const app = new App({ token: "TOKEN", signingSecret: "Signing Secret" });
+const app = new App({ token: 'TOKEN', signingSecret: 'Signing Secret' });
 
 // TODO: Resolve the event type when having subtype in a listener constraint
 // app.message({pattern: 'foo', subtype: 'message_replied'}, async ({ message }) => {});
 
+// TODO: asserting on the types of event sub-properties is a responsibility of the `@slack/types` package, not bolt.
+// e.g. message.user, message.team, etc.
 // Types for generic message listeners, i.e. MessageEvent aka GenericMessageEvent
 app.message(async ({ message }) => {
   expectType<MessageEvent>(message);
 
-  message.channel; // the property access should compile
-
+  expectType<string>(message.channel);
   // The type here is still a union type of all the possible subtyped events.
   // Thus, only the fields available for all the types can be resolved outside if/else statements.
   expectError(message.user);
 
+  // TODO: what if subtype is not on the message at all? e.g. !('subtype' in message)
   if (message.subtype === undefined) {
     expectType<GenericMessageEvent>(message);
     expectNotType<MessageEvent>(message);
+    // TODO: move these assertions to `@slack/types`
     expectType<string>(message.user);
-    expectType<string>(message.channel); // the property access should compile
-    message.team; // the property access should compile
+    expectType<string>(message.channel);
+    // TODO: should this be potentially undefined? Not all of the various Message event subtype interfaces
+    // (in @slack/types) have a `team` property - is that correct? Also the GenericMessageEvent has team as optional.
+    expectType<string | undefined>(message.team);
   }
-  if (message.subtype === "bot_message") {
+  if (message.subtype === 'bot_message') {
     expectType<BotMessageEvent>(message);
     expectNotType<MessageEvent>(message);
-    message.user; // the property access should compile
-    message.channel; // the property access should compile
+    // TODO: move these assertions to `@slack/types`
+    // TODO: should this be potentially undefined?
+    expectType<string | undefined>(message.user);
+    expectType<string>(message.channel);
   }
-  if (message.subtype === "ekm_access_denied") {
+  if (message.subtype === 'ekm_access_denied') {
     expectType<EKMAccessDeniedMessageEvent>(message);
     expectNotType<MessageEvent>(message);
-    message.user; // the property access should compile
-    message.channel; // the property access should compile
+    // TODO: move these assertions to `@slack/types`
+    expectType<string>(message.channel);
   }
-  if (message.subtype === "me_message") {
+  if (message.subtype === 'me_message') {
     expectType<MeMessageEvent>(message);
     expectNotType<MessageEvent>(message);
-    message.user; // the property access should compile
-    message.channel; // the property access should compile
+    // TODO: move these assertions to `@slack/types`
+    expectType<string>(message.user);
+    expectType<string>(message.channel);
   }
-  if (message.subtype === "message_replied") {
+  if (message.subtype === 'message_replied') {
     expectType<MessageRepliedEvent>(message);
     expectNotType<MessageEvent>(message);
-    message.channel; // the property access should compile
-    message.message; // the property access should compile
-    message.message.thread_ts;
+    // TODO: move these assertions to `@slack/types`
+    expectType<string>(message.channel);
+    expectType<string>(message.message.thread_ts);
   }
-  if (message.subtype === "message_changed") {
+  if (message.subtype === 'message_changed') {
     expectType<MessageChangedEvent>(message);
     expectNotType<MessageEvent>(message);
-    message.channel; // the property access should compile
-    message.message; // the property access should compile
+    // TODO: move these assertions to `@slack/types`
+    expectType<string>(message.channel);
+    expectType<AllMessageEvents>(message.message);
   }
-  if (message.subtype === "message_deleted") {
+  if (message.subtype === 'message_deleted') {
     expectType<MessageDeletedEvent>(message);
     expectNotType<MessageEvent>(message);
-    message.channel; // the property access should compile
-    message.ts; // the property access should compile
+    // TODO: move these assertions to `@slack/types`
+    expectType<string>(message.channel);
+    expectType<string>(message.ts);
   }
-  if (message.subtype === "thread_broadcast") {
+  if (message.subtype === 'thread_broadcast') {
     expectType<ThreadBroadcastMessageEvent>(message);
     expectNotType<MessageEvent>(message);
-    message.channel; // the property access should compile
-    message.thread_ts; // the property access should compile
-    message.ts; // the property access should compile
-    message.root; // the property access should compile
+    // TODO: move these assertions to `@slack/types`
+    expectType<string>(message.channel);
+    // TODO: this being potentially undefined seems wrong!
+    expectType<string | undefined>(message.thread_ts);
+    expectType<string>(message.ts);
+    // TODO: the actual type here seems wrong...
+    expectNotType<undefined | null>(message.root);
   }
 
   await Promise.resolve(message);