I also want this and was excited by that blog post too

So far the SourceGraph product ("Cody") is rather underwhelming, it doesn't seem to make deep use of the project context, where the blog post seemed to say that SourceGraph's special sauce would make that possible

The results seem quite similar with Copilot Chat - in both cases they seem to basically stuff the currently focused file as context to your prompt, and the results are no better than if you did the same with ChatGPT, and looks worse because it's cramped into a VS Code sidebar.