diff --git a/.changeset/late-clouds-grow.md b/.changeset/late-clouds-grow.md
new file mode 100644
index 000000000..557bf3fc7
--- /dev/null
+++ b/.changeset/late-clouds-grow.md
@@ -0,0 +1,5 @@
+---
+"@slack/types": minor
+---
+
+feat: add the `app_context_changed` event type for the agent DM experience
diff --git a/packages/types/src/events/app.ts b/packages/types/src/events/app.ts
index a929e0d54..cbfb53ded 100644
--- a/packages/types/src/events/app.ts
+++ b/packages/types/src/events/app.ts
@@ -217,6 +217,40 @@ export interface AppRateLimitedEvent {
 // export interface AppRateLimitedEvent {
 // }
 
+export interface AppContextChangedEvent {
+  type: 'app_context_changed';
+  channel: string;
+  user: string;
+  context: {
+    entities?: ((
+      | {
+          type: 'slack#/types/channel_id';
+          value: string;
+        }
+      | {
+          type: 'slack#/types/canvas_id';
+          value: string;
+        }
+      | {
+          type: 'slack#/types/list_id';
+          value: string;
+        }
+      | {
+          type: 'slack#/types/message_context';
+          value: {
+            message_ts: string;
+            channel_id: string;
+          };
+        }
+    ) & {
+      score?: number;
+      team_id?: string;
+      enterprise_id?: string;
+    })[];
+  };
+  event_ts: string;
+}
+
 export interface AppUninstalledEvent {
   type: 'app_uninstalled';
 }
diff --git a/packages/types/src/events/index.ts b/packages/types/src/events/index.ts
index bb4de42c0..6d7c97301 100644
--- a/packages/types/src/events/index.ts
+++ b/packages/types/src/events/index.ts
@@ -1,4 +1,5 @@
 import type {
+  AppContextChangedEvent,
   AppDeletedEvent,
   AppHomeOpenedEvent,
   AppInstalledEvent,
@@ -120,6 +121,7 @@ export * from './user';
  * This is a discriminated union. The discriminant is the `type` property.
  */
 export type SlackEvent =
+  | AppContextChangedEvent
   | AppDeletedEvent
   | AppHomeOpenedEvent
   | AppInstalledEvent
diff --git a/packages/types/src/events/message.ts b/packages/types/src/events/message.ts
index 060e8cf29..ddb09df4d 100644
--- a/packages/types/src/events/message.ts
+++ b/packages/types/src/events/message.ts
@@ -1,6 +1,7 @@
 import type { Block, KnownBlock } from '../block-kit/blocks';
 import type { BotProfile } from '../common/bot-profile';
 import type { MessageAttachment } from '../message-attachments';
+import type { AppContextChangedEvent } from './app';
 
 type ChannelTypes = 'channel' | 'group' | 'im' | 'mpim' | 'app_home';
 
@@ -60,6 +61,8 @@ export interface GenericMessageEvent {
 
   // TODO: add properties to this field once it's publicly released
   assistant_thread?: Record<string, unknown>;
+
+  app_context?: AppContextChangedEvent['context'];
 }
 
 export interface BotMessageEvent {
diff --git a/packages/types/test/events/app.test-d.ts b/packages/types/test/events/app.test-d.ts
new file mode 100644
index 000000000..e07b94357
--- /dev/null
+++ b/packages/types/test/events/app.test-d.ts
@@ -0,0 +1,75 @@
+import { expectAssignable, expectError } from 'tsd';
+import type { AppContextChangedEvent, SlackEvent } from '../../src/index';
+
+// a channel_id context entity
+const channelContextChangedEvent: AppContextChangedEvent = {
+  type: 'app_context_changed',
+  channel: 'D0123456789',
+  user: 'U0123456789',
+  context: {
+    entities: [
+      {
+        type: 'slack#/types/channel_id',
+        value: 'C0123456789',
+        team_id: 'T0123456789',
+        score: 75,
+        enterprise_id: 'E0123456789',
+      },
+    ],
+  },
+  event_ts: '1234567890.123456',
+};
+expectAssignable<SlackEvent>(channelContextChangedEvent);
+
+// canvas_id and list_id entities share the string `value` shape
+expectAssignable<AppContextChangedEvent>({
+  type: 'app_context_changed',
+  channel: 'D0123456789',
+  user: 'U0123456789',
+  context: {
+    entities: [
+      { type: 'slack#/types/canvas_id', value: 'F0123456789' },
+      { type: 'slack#/types/list_id', value: 'F0123456780' },
+    ],
+  },
+  event_ts: '1234567890.123456',
+});
+
+// a message_context entity carries an object `value` with message_ts and channel_id
+expectAssignable<AppContextChangedEvent>({
+  type: 'app_context_changed',
+  channel: 'D0123456789',
+  user: 'U0123456789',
+  context: {
+    entities: [
+      {
+        type: 'slack#/types/message_context',
+        value: { message_ts: '1234567890.123456', channel_id: 'C0123456789' },
+        team_id: 'T0123456789',
+        score: 75,
+        enterprise_id: 'E0123456789',
+      },
+    ],
+  },
+  event_ts: '1234567890.123456',
+});
+
+// `entities` is optional — the context can be empty
+expectAssignable<AppContextChangedEvent>({
+  type: 'app_context_changed',
+  channel: 'D0123456789',
+  user: 'U0123456789',
+  context: {},
+  event_ts: '1234567890.123456',
+});
+
+// a message_context entity requires channel_id alongside message_ts
+expectError<AppContextChangedEvent>({
+  type: 'app_context_changed',
+  channel: 'D0123456789',
+  user: 'U0123456789',
+  context: {
+    entities: [{ type: 'slack#/types/message_context', value: { message_ts: '1234567890.123456' } }],
+  },
+  event_ts: '1234567890.123456',
+});
diff --git a/packages/types/test/events/message.test-d.ts b/packages/types/test/events/message.test-d.ts
index a215379f3..0cb5df8c6 100644
--- a/packages/types/test/events/message.test-d.ts
+++ b/packages/types/test/events/message.test-d.ts
@@ -23,3 +23,27 @@ const messageDeletedEvent: MessageDeletedEvent = {
   previous_message: anyMessageEvent,
 };
 expectAssignable<MessageEvent>(messageDeletedEvent.previous_message);
+
+// the agent DM context is delivered inline on messages via the `app_context` field
+const messageWithAppContext: GenericMessageEvent = {
+  type: 'message',
+  subtype: undefined,
+  channel_type: 'im',
+  channel: 'D0123456789',
+  user: 'U0123456789',
+  ts: '1234567890.123456',
+  event_ts: '1234567890.123456',
+  text: 'hi',
+  app_context: {
+    entities: [
+      {
+        type: 'slack#/types/channel_id',
+        value: 'C0123456789',
+        team_id: 'T0123456789',
+        score: 75,
+        enterprise_id: 'E0123456789',
+      },
+    ],
+  },
+};
+expectAssignable<GenericMessageEvent>(messageWithAppContext);