Comment, and it acts

The simplest way to delegate a small edit: highlight the line, leave a comment, and your agent picks it up.

It's the same gesture you'd use for a human collaborator, except your agent is the one resolving the threads.

The flow

Highlight the line or paragraph you want changed.
Click the comment button in the right rail, or press ⌘⇧M.
Type a request in the comment box, for example: Tighten this to one line or Turn this into a bulleted list.
Press ⌘↩ to send.

Your agent reads the thread, rewrites the line in place, replies on the thread with a short note of what changed, and the change is saved.

You stay on the page the whole time. The line you commented on is the line that changes, nothing else moves.

While your agent is working:

The line you commented on is highlighted in clay (Claude's color), so you can see it's been picked up.
A clay caret appears on the line and streams the rewrite in, character by character.
A short reply appears under your comment when it's done.

You can resolve the thread when you're happy, or reopen it and ask for another pass.

Be specific. "Tighten this to one sentence" lands better than "make this better."
Comment on the smallest unit that matters. If you want one bullet rewritten, highlight that bullet, not the whole list.
Leave multiple comments at once. Your agent will work through them in order. Useful for a sweep of small fixes across a document.
Use comments for handoffs, not chat. Long back-and-forth is easier in the chat panel. Comments are best for surgical asks on one block.

You can still use comments as a plain notepad, jot a TODO on a line and come back to it later. The thread stays open until you resolve it.