[All Hosts] (overview) Reorienting overview for the M365 ecosystem

docs/develop/develop-overview.md

@@ -2,7 +2,7 @@
 title: Develop Office Add-ins
 description: An introduction to developing Office Add-ins.
 ms.topic: overview
-ms.date: 10/08/2025
+ms.date: 12/10/2025
 ms.localizationpriority: high
 ---
 
@@ -52,9 +52,12 @@ The Office Add-ins Development Kit is an extension for Visual Studio Code. It le
 
 An Office Add-in consists of two parts.
 
-- The add-in manifest that defines the settings and capabilities of the add-in.
+- An app package whose main constituent is an add-in manifest that defines the settings and capabilities of the add-in. The package is the unit of publishing and sideloading. 
 
-- The web application that defines the UI and functionality of add-in components such as task panes, content add-ins, and dialog boxes.
+  > [!NOTE]
+  > An add-in can have either of two types of manifests: the unified manifest for Microsoft 365 or the add-in only manifest. Everything said in this article about the manifest applies to both types. But note that if the add-in only manifest is used, then there is no app package: the manifest file is the unit of publishing and sideloading. For more information about the two types, see [Office Add-ins manifest](../develop/add-in-manifests.md).
+
+- The web application that defines the UI and functionality of add-in components such as task panes, content add-ins, dialog boxes, or Copilot agents.
 
 The web application uses the Office JavaScript API to interact with content in the Office document where the add-in is running. Your add-in can also do other things that web applications typically do, like call external web services, facilitate user authentication, and more.
 
@@ -68,7 +71,6 @@ An Office Add-in's manifest defines the settings and capabilities of the add-in.
 - How the add-in integrates with Office, including any custom UI that the add-in creates (for example, a custom tab or custom ribbon buttons).
 - Location of images that the add-in uses for branding and command iconography.
 - Dimensions of the add-in (for example, dimensions for content add-ins, requested height for Outlook add-ins).
-- Rules that specify when the add-in activates in the context of a message or appointment (for Outlook add-ins only).
 - Keyboard shortcuts (for Excel and Word add-ins only).
 
 For detailed information about the manifest, see [Office Add-ins manifest](add-in-manifests.md).
@@ -113,6 +115,9 @@ The following image shows an add-in command on the ribbon, a task pane to the ri
 
 For more information about extending the Office UI and designing the add-in's UX, see [Office UI elements for Office Add-ins](../design/interface-elements.md).
 
+> [!NOTE]
+> It isn't necessary for an add-in to have any custom UI. An add-in can consist of only a custom Copilot agent that interacts with an Office document in response to natural language instructions given in Copilot chat.
+
 ## Next steps
 
 This article has outlined the different ways to create Office Add-ins, introduced the ways that an add-in can extend the Office UI, described the API sets, and introduced Script Lab as a valuable tool for exploring Office JavaScript APIs and prototyping add-in functionality. Now that you've explored this introductory information, consider continuing your Office Add-ins journey along the following paths.

docs/overview/app-package-for-microsoft-365.md

@@ -0,0 +1,96 @@
+---
+title: App package for Microsoft 365
+description:  Learn how add-ins use the app package for Microsoft 365, for packaging, publishing, and management.
+ms.date: 12/10/2025
+ms.topic: concept-article
+ms.custom: scenarios:getting-started
+ms.localizationpriority: high
+---
+
+# App package for Microsoft 365
+
+The app package of an app for Microsoft 365 is a zip file that contains a manifest file, two app icons, and possibly additional configuration or localization files. Your app logic and data storage are hosted elsewhere and accessed by the Microsoft 365 host application via HTTPS. You'll submit the app package to your admin to publish to your organization or to Partner Center to publish to Microsoft Marketplace.
+
+At minimum, an app package contains:
+
+- The **app manifest** (`manifest.json`), which describes app configuration, capabilities, required resources, and important attributes.
+- A **large full-color icon** (`color.png`), 192 x 192 pixels, to display your agent in the Microsoft 365 Copilot UI and store.
+- A **small outline icon** (`outline.png`), 32 x 32 pixels, with a transparent background (not currently used in Copilot, but required to pass validation).
+
+The app package can also contain declarative agent and API plugin definitions, as well as localization files for other supported languages.
+
+:::image type="content" source="../images/app-package.png" alt-text="Diagram showing the anatomy of a Microsoft 365 app package: app manifest (.json file) + icons (color and outline .png files) wrapped in a .zip file." border="false":::
+
+## App manifest
+
+The unified app manifest for Microsoft 365 is a JSON file that describes the functionality and characteristics of your add-in, such as:
+
+- The add-in's display name, description, ID, version, and default locale.
+
+- How the add-in integrates with Office.  
+
+- How the add-in integrates with Copilot (preview).
+
+- The permission level and data access requirements for the add-in.
+
+For a detailed overview of the manifest, see [Office Add-ins with the unified app manifest for Microsoft 365](../develop/unified-manifest-overview.md). For reference documentation, see [Microsoft 365 app manifest schema reference](/microsoft-365/extensibility/schema).
+
+## App icons
+
+Your app package must include both a color and outline version of your app icon, as .png files. These icons have specific size requirements in order to pass store validation. For detailed design guidance for color and outline icons for the Microsoft 365 app package, see [Design icons for add-in acquisition and management](../design/microsoft-365-extension-management-icons.md).
+
+## Other configuration and localization files
+
+In addition to the manifest and the two icon files, the app package may also contain some of the following files.
+
+- Localization files that are referenced in the `"localizationInfo"` property of the manifest.
+- Copilot declarative agent files that are referenced in the `"copilotAgents"` property.
+- Any second-level supplementary files. For example, Copilot declarative agent configuration files sometimes reference second-level supplementary files, such as Copilot plugin configuration files.
+
+## Manually create the app package file
+
+This app package file is usually created for you by the tools you use to create and test your app for Microsoft 365, but there are scenarios in which you create it manually. To do so, use any zip utility to create a zip file that contains the following files.
+
+- The unified manifest, which goes in the root of the zip file.
+- The two image files referenced in the `"icons"` property of the manifest.
+- Any localization files that are referenced in the `"localizationInfo"` property of the manifest.
+- Any declarative agent files that are referenced in the `"copilotAgents"` property.
+- Any second-level supplementary files. For example, Copilot declarative agent configuration files sometimes reference second-level supplementary files, such as Copilot plugin configuration files. These should be included too.
+
+> [!IMPORTANT]
+> *All of these files must have the same relative path in the zip file as specified in the manifest.* For example, if the path of the two image files is **assets/color.png** and **assets/outline.png**, then you must include an **assets** folder with the two files in the zip package. Second-level files, such as plugin configuration files for declarative agents, must have the same relative path in the zip file as they do in the first-level file that references them. For example, if the relative path of a declarative agent file specified in the manifest is **agents/myAgent.json**, then you must include an **agents** folder in the zip package and put the **myAgent.json** file in it. If the declarative agent file, in turn, gives the relative path of **plugins/myPlugin.json** for a plugin configuration file, then you must include a **plugins** subfolder under the **agents** folder and put the **myPlugin.json** file in it.
+
+To maximize compatibility with Microsoft 365 development tools, we recommend that you keep the files that will be included in the package in a folder called **appPackage** in the root of your project, and that you put the package file in a subfolder named **build** in the **appPackage** folder.
+
+The following are examples of the recommended structure. The structure inside the **\build\appPackage.zip** file must mirror the structure of the **appPackage** folder, except for the **build** folder itself.
+
+```console
+\appPackage
+    \assets
+        color.png
+        outline.png
+    \build
+        appPackage.zip
+    manifest.json
+```
+
+```console
+\appPackage
+    \agents
+        myAgent.json
+        \plugins
+            myPlugin.json
+    \assets
+        color.png
+        outline.png
+    \build
+        appPackage.zip
+    \languages
+        fr-FR.json
+        es-MX.json
+    manifest.json
+```
+
+> [!NOTE]
+> The JSON files that are referenced in the manifest's `"extensions.keyboardShortcuts.keyMappingFiles"` property are *not* included in the app package. They are deployed with the add-in's web application files. For more information, see [Support backward compatibility for add-ins with a unified manifest in Microsoft Marketplace](../design/keyboard-shortcuts.md#support-backward-compatibility-for-add-ins-with-a-unified-manifest-in-microsoft-marketplace).
+