Long Claude conversations have no landmarks. You're 40 exchanges deep into a research thread and the only way to reach an earlier message is to scroll - no jump-to, no anchors, no outline view. A developer built a browser extension that adds all of that.
The extension creates a navigation panel alongside Claude's interface, showing the conversation structure and letting you jump to any point directly. It works like a document outline: useful when you're treating Claude as a working environment rather than a quick chat tool.
Anthropics hasn't shipped this natively. The web interface renders conversations as a continuous scroll with no navigation aids. Whether that reflects deprioritization or something in the interface's design is unclear, but the demand is real enough that community members keep building around it.
One practical note: this is a third-party browser script, not an official Anthropic release. It could break when Claude updates its interface, and installing it grants the extension access to your Claude session data. Review the source code before running it.