GCP – A deep dive into code reviews with Gemini Code Assist in GitHub

Imagine a code review process that doesn’t slow you down. Instead of a queue of pending pull requests, you have an intelligent assistant that provides a near-instant, comprehensive summary of every change. It flags potential bugs, suggests improvements based on best practices, and frees up your human reviewers to focus on the complex architectural decisions that truly require their expertise.

This isn’t a future-state prediction; it’s what’s possible today with Gemini Code Assist, integrated directly into your GitHub workflow at no charge. By embedding a powerful AI partner into every pull request, we’re transforming code reviews from a frustrating bottleneck into a fast and painless way to ensure high quality and consistent code, leading to higher code quality and happier developers.

The challenge: Why code reviews are a bottleneck

Code reviews are a non-negotiable part of building quality software, but they are often a major bottleneck in the development lifecycle. This friction slows down delivery velocity, leads to inconsistent code quality, and makes it difficult to enforce best practices.  Research from DORA’s Impact of Generative AI in Software Development report advises that organizations, “Double-down on fast high-quality feedback, like code reviews and automated testing, using gen AI as appropriate.”   DORA research has found that teams with shorter-code review times have 50% better software delivery performance.¹ AI adoption has been shown to increase code review speed by an estimated 3.1% for every 25% increase in AI adoption, and improve reported code quality by 3.4%.²

The solution: An AI-powered partner in your PRs

Gemini Code Assist integrates into your GitHub workflow as an intelligent partner, conducting code reviews to solve these challenges. When a pull request is created, Gemini is automatically assigned as a reviewer and gets to work immediately. Here’s how it helps:

• Near-instant PR Summaries: Provides a comprehensive summary of the changes to help human reviewers get up to speed almost instantly.
• In-depth automated reviews: Identifies stylistic issues, deviations from best practices, and potential bugs, freeing human reviewers to focus on more critical issues.
• Interactive assistance and learning: Allows anyone in the PR to have a conversation with the AI using /gemini commands to ask for alternative implementations or get a fresh review.

The power of Gemini 2.5: A leap in code review intelligence

With our recent general availability release, Gemini Code Assist has been upgraded to run on our latest model, Gemini 2.5. This isn’t just an incremental update—it’s a major leap forward in the quality, accuracy, and intelligence of AI-powered code reviews.

What does this mean for your daily pull requests?

• Deeper insights: You’ll see more insightful suggestions that go beyond simple style fixes. Gemini 2.5 is better at understanding the logic and intent behind your code, helping to identify potential bugs and suggest more efficient implementations.

• More actionable code suggestions: Through customer specific style guides and configurations, the AI-generated code is now more accurate and context-aware. You’ll find that suggestions are often so reliable that you can commit them with confidence after a quick review, speeding up your iteration cycles.

• Improved relevancy We have significantly increased the relevancy and accuracy of suggestions. This means you can trust the feedback you receive and spend less time second-guessing the AI and more time moving your project forward.

These improvements are a direct result of our rigorous internal testing and deliver more comprehensive and actionable feedback to help developers be more productive.

Customer story: How Delivery Hero enhances code quality with Gemini Code Assist 

Delivery Hero is the world’s leading local delivery platform, operating in around 70 countries.  Strengthening the code review process is a key part of their commitment to delivering high-quality, reliable features for the customers, which prompted them to become an early adopter of the Gemini Code Assist GitHub app.  The initial feedback from their developers was overwhelmingly positive, and the app’s recent upgrade to the Gemini 2.5 model brought an even more significant impact to the app development process, particularly on code quality. Their engineers found the AI-generated comments to be highly relevant and valuable, directly contributing to a higher standard of code. The latest developer experience survey after the adoption of the Gemini Code Assist GitHub app showed a clear rise in developer satisfaction with the quality and speed of code reviews—marking a positive turn for this important metric.  

“By integrating the Gemini Code Assist GitHub app into our workflow, we are not just adopting a tool; we are fostering a more robust, efficient, and collaborative engineering culture.  Our close partnership with Google as an early adopter, built on an agile and effective feedback loop, has been a key part of this success.” N. Mert Aydin,  Principal Software Engineer, Delivery Hero 

Get started

• Try it today: Get started with Gemini Code Assist on the GitHub Marketplace.
• Learn more: Dive deeper by reading the official documentation.

<sup>1.  2023 DORA Report
2. 2024 DORA Report</sup>