diff --git a/packages/teams-js/src/private/hostEntity.ts b/packages/teams-js/src/private/hostEntity.ts
new file mode 100644
index 0000000000..f96ac9c5a8
--- /dev/null
+++ b/packages/teams-js/src/private/hostEntity.ts
@@ -0,0 +1,234 @@
+import { sendMessageToParentAsync } from '../internal/communication';
+import { ensureInitialized } from '../internal/internalAPIs';
+import { ErrorCode, SdkError, TabInstance } from '../public';
+import { runtime } from '../public/runtime';
+
+// Open questions
+// 1. According to Debo, `TabInstance` from the public API looks like it would work. Helen asked Debo to follow up about getting more recent fields added.
+// 2. I didn't see any reason to add a `getTabs` function because `pages.tabs.getTabInstances`. Any reason that won't work for you?
+// 3. I've added an `AppTypes[]` param to `addAndConfigureApp` to allow for the host to show different app types to the user. Helen going to see if there are more types to add here to start.
+// 4. I've added empty, private `validate` functions for the threadId and TabInstance. Any validation that is possible will help prevent against
+//    bad data being sent to the host. If you have any validation that can be done, please add it there. If you *can* use restrictive types like UUID
+//    or something, that would be even better.
+
+// TODO: Add unit tests
+// TODO: Add E2E tests
+
+/**
+ * @hidden
+ * @internal
+ * @beta
+ * Limited to Microsoft-internal use
+ *
+ * TODO: Brief description of what this capability does. For example:
+ * This capability allows an app to associate other apps with a host entity, such as a Teams channel or chat, and configure them as needed.
+ */
+export namespace hostEntity {
+  export enum AppTypes {
+    meeting = 'meeting',
+  }
+
+  /**
+   * @hidden
+   * @internal
+   * @beta
+   * Limited to Microsoft-internal use
+   *
+   * TODO: Brief description of what this capability does. For example:
+   * This capability allows an app to associate other tab apps with a host entity, such as a Teams channel or chat, and configure them as needed.
+   */
+  export namespace tab {
+    /**
+     * @hidden
+     * @internal
+     * @beta
+     * Limited to Microsoft-internal use
+     *
+     * TODO: Add full description of what this function does, ie "Launches host-owned UI that lets a user select an app, installs it if required,
+     * runs through app configuration if required, and then associates the app with the threadId provided. If external docs exist, link to them here"
+     *
+     * @param hostEntityId Info about where this value comes from, links to external docs if available, etc. For example:
+     * The id of the host entity that your app wants to associate another app with. In Teams this would be the threadId <link to docs and more explanation>
+     *
+     * @param appTypes what type of applications to show the user
+     *
+     * @returns The TabInstance of the newly associated app
+     *
+     * @throws TODO: Description of errors that can be thrown from this function
+     */
+    export function addAndConfigure(hostEntityId: string, appTypes: AppTypes[]): Promise<TabInstance> {
+      ensureInitialized(runtime); // TODO: add frameContext checks if this is limited to certain contexts such as content
+
+      if (!isSupported()) {
+        throw new Error(ErrorCode.NOT_SUPPORTED_ON_PLATFORM.toString());
+      }
+
+      validateThreadId(hostEntityId);
+
+      return sendMessageToParentAsync<[boolean, TabInstance | SdkError]>(
+        'apiVersionTag', // TODO: see uses of getApiVersionTag in other files to do this correctly
+        'associatedApps.tab.addAndConfigureApp',
+        [hostEntityId, appTypes],
+      ).then(([wasSuccessful, response]: [boolean, TabInstance | SdkError]) => {
+        if (!wasSuccessful) {
+          // TODO: Can handle error codes differently here, for example if you don't want "user cancelled" to throw
+          const error = response as SdkError;
+          throw new Error(`Error code: ${error.errorCode}, message: ${error.message ?? 'None'}`);
+        }
+        return response as TabInstance;
+      });
+    }
+
+    /**
+     * @hidden
+     * @internal
+     * @beta
+     * Limited to Microsoft-internal use
+     *
+     * TODO: Add full description of what this function does, ie "Allows the user to go through the tab config process again for the specified app. If
+     * no config process exists, X happens, etc."
+     *
+     * @param tab fill in details
+     * @param threadId Info about where this comes from, links to external docs if available, etc.
+     *
+     * @returns The TabInstance of the newly configured app
+     *
+     * @throws TODO: Description of errors that can be thrown from this function
+     */
+    export function reconfigure(tab: TabInstance, threadId: string): Promise<TabInstance> {
+      ensureInitialized(runtime); // TODO: add frameContext checks if this is limited to certain contexts such as content
+
+      if (!isSupported()) {
+        throw new Error(ErrorCode.NOT_SUPPORTED_ON_PLATFORM.toString());
+      }
+
+      validateTab(tab);
+      validateThreadId(threadId);
+
+      return sendMessageToParentAsync<[boolean, TabInstance | SdkError]>(
+        'apiVersionTag', // TODO: see uses of getApiVersionTag in other files to do this correctly
+        'associatedApps.tab.reconfigure',
+        [tab, threadId],
+      ).then(([wasSuccessful, response]: [boolean, TabInstance | SdkError]) => {
+        if (!wasSuccessful) {
+          // TODO: Can handle error codes differently here, for example if you don't want "user cancelled" to throw
+          const error = response as SdkError;
+          throw new Error(`Error code: ${error.errorCode}, message: ${error.message ?? 'None'}`);
+        }
+        return response as TabInstance;
+      });
+    }
+
+    /**
+     * @hidden
+     * @internal
+     * @beta
+     * Limited to Microsoft-internal use
+     *
+     * TODO: Add full description of what this function does, ie "Renames the tab associated with an app"
+     *
+     * @param tab fill in details
+     * @param threadId Info about where this comes from, links to external docs if available, etc.
+     *
+     * @returns The TabInstance of the newly renamed app tab
+     *
+     * @throws TODO: Description of errors that can be thrown from this function
+     */
+    export function rename(tab: TabInstance, threadId: string): Promise<TabInstance> {
+      ensureInitialized(runtime); // TODO: add frameContext checks if this is limited to certain contexts such as content
+
+      if (!isSupported()) {
+        throw new Error(ErrorCode.NOT_SUPPORTED_ON_PLATFORM.toString());
+      }
+
+      validateTab(tab);
+      validateThreadId(threadId);
+
+      return sendMessageToParentAsync<[boolean, TabInstance | SdkError]>(
+        'apiVersionTag', // TODO: see uses of getApiVersionTag in other files to do this correctly
+        'associatedApps.tab.rename',
+        [tab, threadId],
+      ).then(([wasSuccessful, response]: [boolean, TabInstance | SdkError]) => {
+        if (!wasSuccessful) {
+          // TODO: Can handle error codes differently here, for example if you don't want "user cancelled" to throw
+          const error = response as SdkError;
+          throw new Error(`Error code: ${error.errorCode}, message: ${error.message ?? 'None'}`);
+        }
+        return response as TabInstance;
+      });
+    }
+
+    /**
+     * @hidden
+     * @internal
+     * @beta
+     * Limited to Microsoft-internal use
+     *
+     * TODO: Add full description of what this function does, ie "Removes a tab associated with an app, must be called on an app tab, etc."
+     *
+     * @param tab fill in details
+     * @param threadId Info about where this comes from, links to external docs if available, etc.
+     *
+     * @throws TODO: Description of errors that can be thrown from this function
+     */
+    export function remove(tab: TabInstance, threadId: string): Promise<void> {
+      ensureInitialized(runtime); // TODO: add frameContext checks if this is limited to certain contexts such as content
+
+      if (!isSupported()) {
+        throw new Error(ErrorCode.NOT_SUPPORTED_ON_PLATFORM.toString());
+      }
+
+      validateTab(tab);
+      validateThreadId(threadId);
+
+      return sendMessageToParentAsync<[boolean, TabInstance | SdkError]>(
+        'apiVersionTag', // TODO: see uses of getApiVersionTag in other files to do this correctly
+        'associatedApps.tab.remove',
+        [tab, threadId],
+      ).then(([wasSuccessful, response]: [boolean, SdkError]) => {
+        if (!wasSuccessful) {
+          // TODO: Can handle error codes differently here, for example if you don't want "user cancelled" to throw
+          const error = response as SdkError;
+          throw new Error(`Error code: ${error.errorCode}, message: ${error.message ?? 'None'}`);
+        }
+      });
+    }
+
+    /**
+     * @hidden
+     * @internal
+     * @beta
+     * Limited to Microsoft-internal use
+     */
+    export function isSupported(): boolean {
+      throw new Error('Not implemented');
+    }
+
+    function validateThreadId(threadId: string) {
+      // TODO: Any checks you can do on threadId to guarantee valid (not null, not empty, not undefined, format if possible, etc.)
+      /*
+      if (threadId is not valid) {
+        throw new Error(`${threadId} is not a valid threadId`);
+      }
+      */
+    }
+
+    function validateTab(tabInstance: TabInstance) {
+      // TODO: Any checks you can do on TabInstance to guarantee valid (not null, not empty, not undefined, all required properties set to legal values, etc.)
+      /*
+      if (tabInstance is not valid) {
+        throw new Error(`TabInstance ${tabInstance.internalTabInstanceId} is not a valid, extra detail if available`);
+      }
+      */
+    }
+  }
+  /**
+   * @hidden
+   * @internal
+   * @beta
+   * Limited to Microsoft-internal use
+   */
+  export function isSupported(): boolean {
+    throw new Error('Not implemented');
+  }
+}