1. I couldn't send Claude my Markdown Editor selection, or a file I had open as a preview. 2. The claude CLI got none of the editor's context. 3. Claude couldn't run VS Code commands, so it couldn't adapt VS Code to what I was doing. 4. File links in its chat ignored the editor I chose for the file type and opened as raw text (https://github.com/anthropics/claude-code/issues/81482).
So I wrote an extension and a Claude Code plugin that fix those. It turned out useful enough to share.