Lightning-fast menu bar updates with drastically reduced disk work
The numbers on your menu bar will now update instantaneously. Previously, the system relied on a dumb timer that polled your usage once a minute, often lagging far behind reality. Now, it directly listens to your operating system's file events (FSEvents), so the moment you burn through some quota, the on-screen numbers twitch in milliseconds. Not only is it faster, but reading data behind the scenes is much lighter too: it now incrementally parses only the history files that have actually changed, saving your hard drive from redundantly reading identical old files over and over. Additionally, if you run multiple Claude Code sessions in different terminal windows, the system now uses file locks to make them line up politely when saving data, completely preventing them from clobbering each other's usage totals. It's like a restaurant's kitchen flow: waiters used to slowly poke their heads into the kitchen every minute to check for food, but now the kitchen rings a bell the millisecond a dish is ready — and the waiters no longer crash into each other dropping plates on their way out.