Modernize .NET Apps and Add Agentic Functionality in Minutes

TL;DR

• 1

  Managed Instance targets the messy realities of old Windows apps: Azure App Service Managed Instance, announced in public preview last November, is built for dependencies like MSMQ, registry reads and writes, custom MSI installs, local SMTP, drive-letter mounts, and Windows server features.

• 2

  The same app scored very differently depending on the target: In GitHub Copilot's modernization assessment, Gaurav's .NET Framework 4.8 forms app had zero mandatory issues for Azure App Service Managed Instance, but two mandatory issues when targeting standard Azure App Service Windows.

• 3

  The migration story hinges on scripts and adapters, not rewrites: An install.ps1 script handled custom fonts and the SMTP server role, storage mounts recreated H:, K:, and L: style paths, and registry adapters pulled sensitive values from Key Vault secrets at runtime.

• 4

  RDP exists, but only as a troubleshooting escape hatch: Secure Bastion-based RDP lets teams inspect File Explorer, Event Viewer, IIS Manager, and script logs, but any manual instance changes disappear after restart unless they are captured in the installation script.

• 5

  Built-in MCP turns existing APIs into agent tools with no code changes: Upload an OpenAPI 3.0 spec in the new AI blade and App Service maps REST endpoints into MCP tools, letting older business logic plug directly into agent workflows.

• 6

  The demo made the agent story concrete with inventory automation: Jordan's App Service-hosted app used Microsoft Agent Framework with six agents, pulled stock through MCP, detected an out-of-stock navy single-breasted blazer in size small, recommended ordering 15 units from historical sales, and updated inventory automatically.