I built this because I kept losing track of important parts in my long conversations with Claude/ChatGPT.

Threadline adds a sidebar that shows all your messages as a clickable table of contents. Click any entry, jump straight there. Hover to preview the full message before navigating.

Works on both Claude and ChatGPT. Auto-updates as you chat, matches dark/light themes, and stays out of your way when you don't need it.