you can do something like this in cron, too if you don’t want to remember:
1 * * * * claude --model haiku "reply only OK"
another tip: /loop 4m 'cache warm' (with claude; different for other clients). unless you have longer cache times on (is 2x usage with claude), the cache expires after 5 minutes. Sending a msg is about 0.08x the ‘cost’ if it hits the cache. Examples of when the cache can be hit: replying or sending a new msg after it’s been idle for 5+ min, taking more than 5 minutes to answer all questions asked via the tool, a bash script that takes more than 5 min to run. Just having the 4 min loop will fix (1). Unfortunately (2) just needs you to be faster, and for (3) you need the cache warmer + run in bg by default.
If you’ve ever seen a 10% chunk be taken out of your usage super quickly, cache expiry + a longish thread might be why. This is now a much bigger problem (potentially) now that opus with 1m context window was made default.
You can also ask it to use Monitor(heartbeat 4.5m 'keep cache warm') to use the monitor tool which is better than scheduled tasks but not always enabled because anthropic. The Monitor tool sends a msg with every line of stdout. You can use it to make a simple way to send msgs from agent to agent too. It’s so useful I made my own version for opencode.