add working with assessment doc

Author: zhoufenqin

docs/azure/migration/appmod/media/configure-azure-service-target-for-assessment-report.png

@@ -107,5 +107,6 @@ You can choose one of the predefined options and send it in the chat:
 
 ## Next Steps
 
+- [Working with assessment](working-with-assessment.md)
 - [Predefined Tasks](predefined-tasks.md)
 - [Frequently Asked Questions](../../../core/porting/github-copilot-app-modernization/faq.yml)

docs/azure/migration/appmod/media/dotnet-appcat-app-modernization-report.png

@@ -0,0 +1,107 @@
+---
+title: "Working with Assessment: comprehensive guide to application assessment"
+description: Learn how to effectively work with application assessments in GitHub Copilot app modernization, including configuration, interpretation, and report management.
+author: KarlErickson
+ms.author: karler
+ms.reviewer: fenzho
+ms.topic: concept-article
+ms.date: 11/04/2025
+ms.custom: devx-track-dotnet
+---
+
+# Working with Assessment: comprehensive guide to application assessment
+
+This article shows you how to use assessment capabilities in GitHub Copilot app modernization to maximize the value of your application modernization process.
+
+## Overview
+
+Application assessment is a critical first step in your modernization journey. This article shows you how to configure assessments for different scenarios, work with assessment reports, and manage assessment data throughout your modernization process.
+
+## Configure before running assessment
+
+You can edit the configuration for application assessment to specify your target Azure service.
+
+### Configuration properties
+You can edit this file to configure the application assessment. Please note that any changes saved to this file will be applied the next time you run the assessment.
+
+The configurable AppCAT arguments
+
+- Target:
+
+Target means the Azure compute service to run the apps on. Choose "Any" if you haven't decided which one to use and later you can choose and compare on the assessment report. By default, it's set as `Any`.
+
+| Target                            | Description                                                        |
+|-----------------------------------|--------------------------------------------------------------------|
+| Any                               | Discover issues for all supported targets here.                    |
+| AKS.Windows                       | Best practices for Azure Kubernetes Service (Windows).             |
+| AKS.Linux                         | Best practices for Azure Kubernetes Service (Linux).               |
+| AppService.Windows                | Best practices for Azure App Service (Windows).                    |
+| AppService.Linux                  | Best practices for Azure App Service (Linux).                      |
+| AppServiceContainer.Windows       | Best practices for Azure App Service Container (Windows).          |
+| AppServiceContainer.Linux         | Best practices for Azure App Service Container (Linux).            |
+| AppServiceManagedInstance.Windows | Best practices for Azure App Service Managed Instance (Windows).   |
+| ACA                               | Best practices for Azure Container Apps.                           |
+
+### Examples
+
+The following are two examples of how to configure properly.
+
+- Example one: you'd like to migrate your apps to Azure but haven't decided on the target compute service yet.
+```json
+{
+  "appcat": {
+    "target": "Any"
+  }
+}
+```
+
+- Example two: you'd like to migrate your apps to App Service Linux and want to understand what are the issues to be fixed.
+```json
+{
+  "appcat": {
+    "target": "AppService.Linux"
+  }
+}
+```
+
+:::image type="content" source="media/configure-azure-service-target-for-assessment-report.png" lightbox="media/configure-azure-service-target-for-assessment-report.png" alt-text="Screenshot of Visual Studio that shows the GitHub Copilot app modernization assessment configuration.":::
+
+
+After running an assessment, the interactive dashboard opens automatically, providing comprehensive analysis results. When you configure the AppCAT target Azure service as `Any`, you can switch between them to compare migration approaches and view service-specific recommendations. If you configure the target Azure service as a specific one, you can only see one Azure service in the dropdown list.
+
+:::image type="content" source="./media/list-azure-service-target-for-assessment-report.png" lightbox="./media/list-azure-service-target-for-assessment-report.png" alt-text="Screenshot of Visual Studio showing the GitHub Copilot app modernization assessment dashboard with Azure service target selection options.":::
+
+## Operate Assessment Report
+
+Effective report management enables collaboration, maintains assessment history, and integrates with existing workflows.
+
+### Import assessment report
+
+Besides running the assessment directly in GitHub Copilot app modernization, you can also import assessment reports. The report can come from a .NET AppCAT CLI result or from a GitHub Copilot app modernization exported report.
+
+The following example shows how to import a report from an AppCAT CLI result. Choose `Save as App Modernization Report` when running AppCAT. After that, you can import the report into GitHub Copilot app modernization.
+:::image type="content" source="./media/dotnet-appcat-app-modernization-report.png" lightbox="./media/dotnet-appcat-app-modernization-report.png" alt-text="Screenshot of AppCAT CLI showing the App Modernization Report chosen.":::
+
+
+You can trigger importing a report by typing "import assessment report" in the chat when you enter the `Modernize` agent, or select the `Import` button in the assessment dashboard to import the report from the file explorer.
+
+:::image type="content" source="./media/import-assessment-report-in-chat.png" lightbox="./media/import-assessment-report-in-chat.png" alt-text="Screenshot of Visual Studio showing the GitHub Copilot app modernization assessment report import from chat.":::
+
+:::image type="content" source="./media/import-assessment-report.png" lightbox="./media/import-assessment-report.png" alt-text="Screenshot of Visual Studio showing the GitHub Copilot app modernization assessment report import interface.":::
+
+### Export assessment report
+
+In the assessment dashboard, you can view the issues detected by AppCAT and choose the migration solution. You can export the report and share it with others. This way, other people don't need to run the assessment themselves and can import the report to view the assessment and migration decisions directly.
+
+You can select the `Export` button in the assessment dashboard to export the report to the file explorer.
+
+
+:::image type="content" source="./media/export-assessment-report.png" lightbox="./media/export-assessment-report.png" alt-text="Screenshot of Visual Studio showing the GitHub Copilot app modernization assessment report export options and interface.":::
+
+
+
+## Next Steps
+
+- [Predefined Tasks](predefined-tasks.md)
+- [Frequently Asked Questions](../../../core/porting/github-copilot-app-modernization/faq.yml)
+

docs/azure/migration/appmod/media/export-assessment-report.png

@@ -32,6 +32,8 @@ items:
           href: ../core/porting/github-copilot-app-modernization/faq.yml?toc=/dotnet/azure/toc.json&bc=/dotnet/breadcrumb/toc.json
         - name: Predefined Tasks
           href: ./migration/appmod/predefined-tasks.md
+        - name: Working with assessment
+          href: ./migration/appmod/working-with-assessment.md
         - name: Quickstart - Assess and migrate a .NET project
           href: ./migration/appmod/quickstart.md
         - name: Quickstart - Containerize a .NET project