A copilot is an AI-based assistant built into a piece of software that suggests code, text or actions in real time, which the user accepts, edits or rejects.
The term comes from GitHub Copilot, launched in 2021 by GitHub (a Microsoft subsidiary) with OpenAI: it completes code directly in the editor. Microsoft then extended the Copilot brand to its other products, from Windows to the Microsoft 365 suite. The word has become a generic name for any assistant of this kind.
In software development the offer is broad: GitHub Copilot, Cursor, JetBrains AI Assistant, Claude Code, Windsurf, Tabnine… The line with agents is blurring: these tools no longer just complete a line, they can edit several files or run commands.
The distinction is still useful: a copilot suggests and the human approves each step, while an agent chains several actions on its own toward a goal.
Why it matters when hiring
Almost every developer uses a coding assistant, so it is no longer a differentiator. The good signal in an interview: being able to say where the tool saves time, where it gets things wrong, and how its output is reviewed. The opposite trap exists too: a candidate who can no longer reason without the tool. A code reading or debugging exercise reveals it quickly.