The past few years of programming have been some of the most frenetic I have experienced since I started developing software professionally. The rise of large language models and AI has forever changed software development. I have incorporated different tools and processes into my workflow throughout these past few years. The tools I am using most frequently as of early 2026 are:

• GitHub Copilot agent mode in Visual Studio 2026 and in VS Code
• Claude Sonnet/Opus 4.5
• Custom Agents
• MCP servers/tools

I have had the most success in Visual Studio with GitHub Copilot paired with Claude Sonnet or Opus 4.5. This seems to track with the majority of users of GitHub Copilot.

A custom agent feature was recently added to VS Code (and I’m assuming will be coming to Visual Studio 2026). Per the docs:

Custom agents enable you to configure the AI to adopt different personas tailored to specific development roles and tasks. For example, you might create agents for a security reviewer, planner, solution architect, or other specialized roles. Each persona can have its own behavior, available tools, and instructions.

I experimented with custom agents recently to upgrade a .NET solution with multiple projects to .NET 10. The dotnet-upgrade.agent.md agent I used can be viewed here. I used an agent I found in the awesome-copilot repo and modified it for use with the new custom agent syntax in VS Code. I was impressed with how well it worked. It did a few things that I needed to revert and change, but for the most part, it did a great job.

The tools these agents use can include built-in tools, tool sets, MCP tools, or tools contributed by extensions. My dotnet-upgrade.agent currently includes the following tools:

['search', 'edit/editFiles', 'runCommands', 'runTasks', 'problems', 'changes', 'usages', 'testFailure', 'runCommands/terminalLastCommand', 'runCommands/terminalSelection', 'fetch', 'todos', 'microsoft-learn/*']

microsoft-learn/* included above is the Microsoft Learn MCP Server provided by Microsoft: https://learn.microsoft.com/en-us/training/support/mcp

At my day job, we currently use the Telerik UI for Blazor component library. Before integrating MCP tools, Copilot seemed to lack the requisite knowledge of Blazor and Telerik components. After adding the Telerik Blazor MCP Server, code generation became much better. I was able to create a nice-looking dashboard using agent mode and the Telerik Blazor MCP server without much backtracking and hand-holding with Copilot.

If you haven’t experimented with MCP and custom agents much yet, I definitely recommend giving it a try. Things seem to be improving every few months.