GitHub Copilot: C++ Modernization Agent Now Generally Available
GitHub CopilotGitHub Copilot's modernization agent for C++ has graduated from public preview to general availability in Visual Studio, giving C++ teams an AI agent that automates upgrading legacy projects to newer MSVC Build Tools. The agent works in either Automated mode (end-to-end upgrade) or Guided mode (step-by-step review of assessment, plan, and execution), and handles both MSBuild (.sln, .vcxproj) and CMake-based projects. It resolves common upgrade breakage such as deprecated CRT functions, stricter C++ conformance errors, removed experimental namespaces, and linker errors from removed Windows SDK APIs. The capability is available on every Copilot plan, from Free and Student up through Business and Enterprise.
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A New Agent for an Old Problem
Upgrading a legacy C++ codebase to a current MSVC toolchain has historically been slow, manual work: tracking down deprecated CRT calls, chasing new compiler warnings, and untangling linker errors introduced by removed Windows SDK APIs. GitHub Copilot's modernization agent, first previewed for C++ developers in late 2025, now ships generally available in Visual Studio as of the June 2026 update, specifically covering MSVC upgrade scenarios.
How the Agent Works
Developers can invoke the agent by right-clicking a project in Solution Explorer and selecting "Modernize," or by typing @Modernize directly in Copilot Chat. From there, the agent walks through three stages: it first assesses the project, cataloging every upgrade-related issue it finds; it then proposes a plan describing how each issue will be resolved; and finally it executes that plan as a sequence of discrete tasks.
Two modes control how much oversight a developer wants during that process. Automated mode runs the full assessment-plan-execution pipeline end to end with minimal intervention, suited to large, well-tested codebases where a hands-off upgrade is acceptable. Guided mode instead pauses at each stage so a developer can review and approve the assessment, the proposed plan, and each execution step before it's applied, which matters for codebases where an automatic fix might carry more risk.
Project Support and Fixes
The agent supports both MSBuild-based projects (.sln and .vcxproj files) and CMake-based projects, and updates project settings as part of the upgrade. Beyond simple version bumps, it resolves the kinds of breakage that typically make MSVC upgrades painful in practice: deprecated CRT functions, stricter C++ conformance checks that break code compiling loosely on older toolchains, removed experimental namespaces, new or elevated compiler warnings, and linker errors caused by Windows SDK APIs that no longer exist in newer SDK versions.
Availability
The modernization agent for C++ is accessible to every GitHub Copilot plan tier, including Copilot Free and Student, not just paid Business and Enterprise tiers, making it broadly available to individual developers and hobbyists working on older C++ projects as well as enterprise teams managing large legacy estates.