Copilot is an extension for VS Code that does integration of their supported AI models with code editor (including creation/removal/moving/renaming/editing files, providing git-like diffs and per-file keep/discard choices for what AI made in response to your most recent prompt, etc). They only support fixed set of models and don’t provide any way to integrate free / opensource models. So the question is mainly what’s the alternative to Copilot for free models.