The art of simplicity

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GitHub Copilot SDK–Breaking change in permission handling

If you looked at an older GitHub Copilot SDK example online and copied it over, there is a chance that you see the following error message when you try to execute the code: Unhandled exception. System.ArgumentException: An OnPermissionRequest handler is required when creating a session. For example, to allow all permissions, use CreateSessionAsync(new() { OnPermissionRequest = PermissionHandler.ApproveAll }); at GitHub.Copilot.SDK.CopilotClient.CreateSessionAsync(SessionConfig config, CancellationToken cancellationToken) So, what exactly is happening here? The important part is this: An OnPermissionRequest handler is required when creating a session. The GitHub Copilot SDK is designed with a permission-based execution model . Whenever Copilot wants to execute a tool, access resources, or perform potentially impactful operations, the SDK expects the host application to decide whether that action is allowed. This is done through the OnPermissionRequest callback. With older...

Sessions in the GitHub Copilot SDK: What they are and how to manage them

In the previous post we got a working .NET app talking to the Copilot agent runtime. We created a CopilotSession , sent messages through it, and saw how multi-turn conversations just work — the agent remembered what you said three messages ago without you having to manage that state yourself. That "just works" quality is deliberate, and it's worth understanding what's actually happening underneath. Sessions are the stateful core of the Copilot SDK. How you create, configure, scope, and dispose them determines whether your application is resilient, scalable, and cost-efficient — or fragile and leaky. This post goes deep on sessions: what they are, how their lifecycle works, how to persist them across restarts, and the patterns that hold up in production. The mental model: Client vs. Session Before getting into lifecycle specifics, it's worth being precise about the two core classes and what each one owns. CopilotClient is infrastructure. It manages th...

Getting started with the GitHub Copilot SDK in .NET

In the previous post talked about why the GitHub Copilot SDK matters: it gives you a production-grade agent harness out of the box, so you can skip building the infrastructure and focus on your actual product. Now let's make it concrete. This post walks through everything you need to get up and running with the SDK in .NET — from prerequisites to a working streaming agent with a custom tool. What we will build We’ll keep it simple. By the end of this post you'll have a console application that: Connects to Copilot's agent runtime Sends a prompt and receives a streaming response Has a multi-turn conversation with persistent context Calls a custom tool you define in C# Prerequisites You'll need three things before touching any code. 1. .NET 8 or later The SDK requires .NET 8+. Verify your version: dotnet --version 2. GitHub Copilot CLI, installed and authenticated The SDK communicates with the Copilot CLI running as a local process — it...

You don't need to build your own agent harness

Building an agent sounds straightforward until you actually start. Before you write a single line of business logic, you're already deep in infrastructure decisions: How do you manage context across multiple turns? How do you orchestrate tool calls? How do you handle model routing, MCP server integration, permissions, failure modes, and safety boundaries? By the time you've answered all those questions, you've quietly built a small platform — and you haven't shipped anything yet. This is the tax that every team building agentic applications has been paying. Until now... Meet the GitHub Copilot SDK GitHub launched the Copilot SDK in technical preview in January 2026, and its core value proposition is refreshingly direct: stop building the harness, start building your product . The SDK gives you programmatic access to the same production-tested execution loop that powers GitHub Copilot CLI. That means the planning, tool invocation, multi-turn context management,...

We are all beginners

While visiting multiple organizations and talking to colleagues about integrating AI into their software development lifecycle, I noticed something: The approaches couldn’t have been more different. Some teams were embedding AI deeply into every step of development—coding, testing, documentation, even architectural decision-making. Others were deliberately cautious, limiting AI to narrow, controlled use cases. Opposites. And yet, both felt… reasonable. That’s when it clicked for me: We are all beginners. Not in the dismissive sense. Not in a “we don’t know anything” kind of way. But in the ways as described inside the Dreyfus Model of Skill Acquisition . The Dreyfus model, briefly The Dreyfus model describes how people acquire skills through five stages: Novice – Rely on rules and rigid guidelines Advanced Beginner – Start recognizing patterns, but still need support Competent – Can plan, prioritize, and make conscious de...

How to use GitHub Copilot Agent Skills in Visual Studio

With the introduction of agent skills , we can teach our AI agent to handle our most repetitive and specialized workflows. After adding context through an agent.md file, integrating tool calls using MCP, creating our own Agents, this is a logical next step in defining your AI enabled software development lifecycle. Here's everything you need to know to get started. What are agent skills? Agent skills are folders of instructions, scripts, and resources that GitHub Copilot can load automatically when relevant to your prompt. Think of them as reusable "playbooks" you write once and invoke repeatedly — without having to re-explain the context every time. Unlike custom instructions , which set broad coding guidelines that apply across nearly every task, skills are meant for specialized, on-demand capabilities: things like running a specific test suite, converting file formats, generating components, or following a custom deployment checklist. How to create your firs...