I couldn't find a tool that would let me work with Claude as a true collaborator on a document, so we are making one together! Tandem is real-time collaboration between you and the same Claude Code that already has access to your domain knowledge, skills, plugins, etc.

Annotate, highlight, ask questions about specific snippets of text, and chat, all in the browser window. It is still pretty early, and channels are still an experimental feature, but it already feels way better than the annoying back and forth process that I was using before.