Microsoft is using AI copilot internally for code reviews impacting 600,000 PRs per month

Microsoft has shared its findings from using AI inside the firm to review code, impacting over 600,000 pull requests per month.

Spectacles on a table in front of laptop with both glasses having logos of Microsoft Copilot

GitHub Copilot is a fairly impressive tool that can use the power of generative AI (GAI) to write both boilerplate and arguably complex code on your behalf. Microsoft recently open-sourced the coding assistant's implementation in Visual Studio Code so that other developers can build upon it too. Now, the company has shared some details about how heavily it is utilizing AI assistants in its own development processes.

Microsoft says that it utilizes its in-house AI-powered coding assistant for code reviews. This tool impacts over 600,000 pull requests (PRs) per month, encapsulating almost 90% of the company's total PRs. This coding review assistant doesn't have a specific name, but it was built with the help of the Developer Division's AI & Data team, and the learning during this process was then used in GitHub Copilot code reviews to benefit external customers too.

The Redmond tech firm says that a major issue with code reviews at scale is that reviewers sometimes focus too much on syntax and ignore more critical issues, while code authors often struggle to define context in complex PRs. This also results in PRs getting delayed, which is where AI-powered code reviews come into play, as they solve most of these problems in a relatively short period of time.

This code review assistant can automatically check the code, make comments, flag issues, suggest improvements and optimizations, and generate a summary of the PR. Human reviewers can also engage in a Q&A session with the assistant to understand the code better. Teams also have the option to configure the assistant and tailor it to a specific problem through customized prompts.

Microsoft has boasted the positive impact of this process, citing faster review cycles, improved code quality, and learning opportunities for developers and reviewers. The firm believes that this is the future of coding, which is also why it decided to share its own learning and tooling with external customers through GitHub Copilot code reviews - which became generally available in April 2025. We just hope that Redmond's internal AI tool isn't responsible for the Windows Vista startup sound in Windows 11.