How to Use Cody AI to Understand and Refactor Large Codebases

Understanding and refactoring a large codebase is one of the hardest tasks in software development, especially when you are new to a project. Cody by Sourcegraph changes this by giving you an AI assistant that reads your entire repository and answers questions with real code context.

Why Repository-Wide Context Matters

Generic AI chat tools only see the code you paste in. Cody uses Sourcegraph’s code intelligence to follow references across files, meaning its answers are grounded in your actual codebase rather than guesswork.

Step 1: Install Cody in Your Editor

Install the Cody extension for VS Code, JetBrains, or Neovim from the available marketplaces. Sign in with your Sourcegraph account, then open the project you want to work on.

Step 2: Ask Questions About Your Code

Use the chat panel to ask questions like “Where is the payment logic handled?” or “How does authentication work here?” Cody will read the relevant files and explain the flow with references you can click to jump directly to the code.

Step 3: Generate Tests and Documentation

Select a function and ask Cody to generate unit tests or documentation. It uses the surrounding code to produce accurate, idiomatic output that fits your project’s conventions.

Step 4: Refactor with Confidence

Before refactoring, ask Cody to identify all the places a function is used and suggest safe changes. This reduces the risk of breaking dependent code and speeds up large restructuring tasks.

Step 5: Use Cody from the Command Line

Install the Cody CLI to ask questions, scan code for issues, and get answers without leaving your terminal, which is handy for CI and remote work.

With Cody, developers can onboard faster, write better tests, and refactor large systems with far less risk.