GitHub Copilot is the AI coding assistant GitHub built with OpenAI, and it's the product most people mean when they say AI autocomplete for code. It plugs into VS Code, Visual Studio, JetBrains IDEs, and Neovim, suggesting completions as you type based on training over a huge amount of public code and natural language text.
It reads more than the current line: a comment describing what a function should do is often enough for Copilot to generate a working implementation, and it picks up on the conventions already in a project so suggestions tend to match the existing style rather than looking bolted on. Beyond straight completion, it now includes a chat interface, automated PR review comments, and an agent mode that can carry out multi-step coding tasks with less hand-holding.
None of that removes the need to read what it writes. Copilot's suggestions come from patterns in its training data, which means output can be subtly wrong, inefficient, or insecure in ways that only show up under review or in production. GitHub has always framed it as a tool that speeds up a developer, not one that replaces their judgment, and in practice that's still the right way to use it.