As part of PR #3094, the following alternative would also work:

<form hx-target="#notes" hx-swap="afterbegin">
    <div>
        <label>Add a note</label>
        <input type="text" name="note-text" placeholder="blank canvas">
    </div>
    <button type="reset" hx-post="/note">Add</button>
</form>
<ul id="notes"><!-- Response will go here --></ul>

EDIT: I originally didn't see the part about only resetting on successful requests which my example doesn't handle

As part of PR #3094, the following alternative would also work:

Good point, that would probably work for the example used in the issue. I do think resetting only on successful requests is an important stipulation, though (we wouldn't want to reset a username on failed login, for example). This method also can be extended to elements that aren't forms. Maybe "reset user input" would be a better name.