Definition
Code Review
Code review is the practice of having one or more engineers examine a change before it merges, checking for correctness, clarity, security, and adherence to conventions. Beyond catching defects, it spreads knowledge across the team, enforces shared standards, and creates a documented rationale for why code looks the way it does — typically conducted on a pull request.
Key takeaways
- Code review is examining a change before it merges for correctness, clarity, security, and adherence to conventions.
- Its value goes beyond catching bugs: it spreads knowledge, enforces shared standards, and documents why code looks the way it does.
- Small, focused changes get far better scrutiny than sprawling ones, and reviewers should separate blocking concerns from optional nits.
- Automated checks (linters, tests, formatters) should handle mechanical issues so humans focus on design and intent.
A code review is a deliberate second pair of eyes on a proposed change. The author opens a pull request describing what changed and why; reviewers read the diff, ask questions, request changes, and ultimately approve. The immediate value is defect detection — bugs, edge cases, and security flaws are far cheaper to catch here than in production.
The deeper value is cultural. Review is how conventions actually propagate: a standard nobody enforces is a suggestion, and review is where it's enforced kindly and consistently. It spreads knowledge, so no part of the codebase has exactly one person who understands it. And the recorded discussion becomes durable documentation of the reasoning behind a decision.
Effective review has norms. Small, focused changes get better scrutiny than sprawling ones. Reviewers separate blocking concerns from optional nits and explain the why behind requests. Authors respond to feedback rather than defending. Automated checks — formatters, linters, tests — handle the mechanical issues so humans focus on design, correctness, and intent.
Planoda's AI agents can perform a first-pass review on a pull request under propose/approve governance — surfacing likely issues for a human to confirm — with every suggestion captured in the audit trail.
Related terms
- Pull RequestA pull request (PR), also called a merge request, is a proposal to merge a set of code changes from one branch into another. It packages a diff with a description, opens it for review and discussion, runs automated checks, and serves as the gate where changes are inspected and approved before they enter the main codebase.
- CI/CD (Continuous Integration / Continuous Delivery)CI/CD is the practice of automatically building, testing, and releasing code through a pipeline triggered by every change. Continuous integration merges and verifies work frequently to catch conflicts early; continuous delivery keeps the software always in a releasable state, often deploying automatically. Together they shorten the path from a commit to running in production.
- Technical DebtTechnical debt is the implied future cost of choosing an easier or faster solution now over a better one that takes longer. Like financial debt, it accrues interest: shortcuts in code, architecture, or tests slow every future change until they're repaid through refactoring. Some debt is deliberate and strategic; some is accidental and corrosive.
- Definition of DoneA definition of done is a shared, explicit checklist of what must be true before any work item counts as complete — code reviewed, tests passing, documentation updated, deployed. It removes ambiguity about the word 'done,' preventing half-finished work from being declared finished and creating a consistent quality bar across the whole team.
- Propose / Approve (AI Governance)Propose/approve is a governance pattern for autonomous software: instead of executing a consequential action directly, an AI agent emits it as a proposal that a human or policy must approve before it runs. It keeps fast, read-only work autonomous while gating destructive or irreversible operations — the practical way to give agents real power without surrendering control.