-description: Learn how to build a message extension using an OpenAPI description document (API).

->[!IMPORTANT]

-> You can build an API-based message extension now and starting early next year, the extensions will function as plugins within Copilot and enhance Copilot experience for your extensions.

-You can create an API-based message extension using Visual Studio Code, Teams Toolkit CLI, or Visual Studio.

-<!--# [Developer Portal for Teams](#tab/developer-portal-for-teams)

-1. Enter a name of the app and select **Add**.

-1. In the left pane, under **Configure**, select **App features**.

-1. Under **Message extension type**, select **API-based**.

-1. If you get a disclaimer which reads **Bot message extension is already in use by users. Would you like to change message extension type to API?**, select **Yes, change**.

-1. Under **Open API spec**, select **Upload now**.

-1. Select the Open OpenAPI Description document in JSON or YAML and select **Open**.

- :::image type="content" source="../assets/images/Copilot/api-based-me-tdp-api-saved.png" alt-text="Screenshot shows an example of the the API spec saved successfully message and Got it button.":::

-> Message extensions built from an API only support single parameter.

- A **Add a command** pop-up appears with a list of all the available APIs from the Open API Description document.

- A **Add a command** page appears.

-1. In the **Add command** page, go to **Adaptive card template** and select **Upload now**.

- :::image type="content" source="../assets/images/Copilot/api-based-me-tdp-adaptive-card-template.png" alt-text="Screenshot shows the Upload now option to add the adaptive Card template in for the command.":::

- > If you have more than one API, ensure that you upload the **Adaptive card template** for all the APIs.

-1. If you want to launch a command using a trigger in Microsoft 365 chat, Turn on the **Automatically run the command when a user opens the extension** toggle.

- :::image type="content" source="../assets/images/Copilot/api-based-me-tdp-plugin-copilot.png" alt-text="Screenshot shows the plugin for copilot app created in the app features page in Teams Developer Portal.":::

-An API message extension is created. -->

- :::image type="content" source="../assets/images/Copilot/api-based-me-vs-create-project.png" alt-text="Screenshot shows the Search results from API, New API, OpenAPI Description Document, and Create options in Visual Studio to create a new Project.":::

- |`Models/RepairModel.cs`|Defines a data model that represents a repair task with properties such as Id, Title, Description, AssignedTo, Date, and Image.|

-You can create a bot-based search message extension using Teams Toolkit for Visual Studio Code, Visual Studio, or CLI and extend the message extension to function as a plugin in Copilot for Microsoft 365.

-<!--# [Developer Portal for Teams](#tab/developer-portal-for-teams)

-1. Select **Create a new app**.

- 1. If don't have a Bot ID, you can select **Create a bot**, to create a new bot and enter the bot ID of the new bot that you've created.

-1. In the **Add a command** page, select the **Search** as the type of command and update the following:

-A bot-based message extension is created.

-1. [How will the dialog (referred as task module in TeamsJS v1.x) be created?](#select-how-to-create-your-dialog)

-1. [Will the final message or card be sent to the channel from a bot, or will the message or card be inserted into the compose message area for the user to submit?](#select-how-the-final-message-is-sent)

-First, you must decide the location from where your action command must be invoked. By specifying the `context` in your app manifest (previously called Teams app manifest), your command can be invoked from one or more of the following locations:

- 1. If you don't have a bot ID, select **Create a bot**, to create a new bot and enter the bot ID of the new bot that you've created.

-1. Select **Action** as the type of command and update the following:

-1. Select ellipse under command section and then select **Edit parameter**.

-1. Select **Add a Parameters** and enter all the parameters.

-A search message extension using bot framework is created.

-When a search command is invoked from the compose message area, the user sends the results to the conversation. When it's invoked from the command box, the user interacts with the resulting card, or copies it for use elsewhere.

-* [Set up your dev environment for extending Teams apps across Microsoft 365.](../../../m365-apps/prerequisites.md) After you've enrolled your developer tenant in Office 365 Targeted Release, it may take a couple of days for the enrollment to take effect.

- 1. If you don't have a bot ID, select **Create a bot**, to create a new bot and enter the bot ID of the new bot that you've created.

-1. In the Command details page, select **Search** as the type of command and update the following:

-1. At the upper-right, select **Preview in Teams**. The app opens in Teams desktop or web client.

-|Teams message extension search | This sample shows how to build a search-based message extension. It searches nudget packages and displays the results in search-based messaging extension. |[View](https://github.com/OfficeDev/Microsoft-Teams-Samples/tree/main/samples/msgext-search/csharp)|[View](https://github.com/OfficeDev/Microsoft-Teams-Samples/tree/main/samples/msgext-search/nodejs)|[View](https://github.com/OfficeDev/Microsoft-Teams-Samples/tree/main/samples/msgext-search/csharp/demo-manifest/msgext-search.zip)

-***February 06, 2024***: [Introduced systemDefault reserved activity type for send activity feed notifications](tabs/send-activity-feed-notification.md#requirements-to-use-the-activity-feed-notification-apis).