TL;DR: AI will not replace human code review. Instead, it will augment it. AI excels at automating low-level, objective checks like style violations and common bugs. Humans remain essential for high-level, subjective tasks that require business context, architectural judgment, and mentorship.
What is the role of AI in code review?
AI's primary role in code review is to act as a powerful assistant that automates the first layer of feedback. By handling objective, low-level issues, AI companions free up human reviewers to focus on more complex, high-impact concerns.
AI is most effective at the following tasks:
Automating low-level feedback: AI can instantly check for style guide violations, improper formatting, or lack of documentation. This offloads the burden of "nit-picking" from human reviewers, a practice that Google found to be a valuable time-saver in its Tricorder project.
Catching common pitfalls and security vulnerabilities: Modern LLMs are trained on vast datasets of open-source code, making them effective at identifying common programming errors, race conditions, or potential security risks like SQL injection and buffer overflows.
Validating test coverage: An AI can scan a pull request and quickly determine if the changes are accompanied by adequate tests, ensuring that new logic doesn't degrade the reliability of the codebase.
What are the limits of AI in code review?
AI's primary limitation is its lack of subjective understanding. The most critical feedback in a review session involves context, judgment, and foresight, which are areas where human expertise remains irreplaceable.
Why can't AI understand business context?
AI cannot understand business context because that information often lives outside the codebase in project management tools, design documents, and team meetings. An LLM can validate that code is syntactically correct, but it has no understanding of the *why* behind the code.
A human reviewer, however, can ask critical questions that an AI cannot:
Does this change align with the product roadmap and the user story in the ticket?
Does this implementation account for the business trade-off we discussed last week?
Is this the right problem to be solving right now?
Why does architectural review still require humans?
Architectural review requires humans because AI models excel at "local" reasoning within a single file but struggle with the "global" reasoning needed to maintain a large-scale system.
A senior engineer can evaluate a change's long-term impact, determining if it introduces a problematic dependency, violates a domain boundary, or should be implemented in a different microservice. This architectural oversight is essential for preventing technical debt and maintaining a scalable system.
Can AI replace the mentorship aspect of code review?
No. Code review is a critical process for knowledge sharing and team development, which AI cannot replicate. Studies from Microsoft Research have shown that key goals of code review include finding better solutions and transferring knowledge.
An AI can tell you that your code is inefficient, but a senior developer can explain why a different approach is better in the context of your specific system. This mentorship loop is critical for team growth and cannot be automated.
What is the best model for using AI in code review?
The most effective model is not replacement, but augmentation. In this model, AI and humans work together, each focusing on the tasks they are best suited for.
The ideal workflow uses AI to handle the first pass of a review. The AI companion flags all the low-level issues—style violations, potential bugs, and missing tests—before a human ever sees the pull request.
This allows the human reviewer to focus entirely on what matters most: the quality of the solution, its architectural integrity, and its business logic. The conversation shifts from "you missed a comma here" to "have you considered how this will scale in the future?"
This is the philosophy behind Graphite's platform. Tools like Graphite Agent act as a companion in the review process, automating the tedious work so developers can have more meaningful, high-level discussions. The goal is to build a workflow where human time is spent on the problems only humans can solve.
