I feel like the half hour is just the default send interval for errors, but still. I've also been getting these intermittently, and as far as I can tell I shouldn't be. I'll admit, I don't have any mechanism to stop my script once I reach a certain amount of used cpu, but I'm also pretty sure I have nothing that should ever cause a hard reset. I suppose I wouldn't be surprised at the very rare soft reset (although from my stat tracking I feel like this hasn't happened in ages either), but again, I see no cause in my code for hard resets. I know others have had intermittent issues with this as well.

I would love access to the FIND registers and the intents.set object! Also, as an alternative to reducing move cost, perhaps there could be a reduced cost for creeps doing multiple actions? Something like the first action costs .2, then any subsequent actions only cost .1. I feel like this could alleviate a lot of cpu for creeps that move + some action(s) on the same tick. This is based off my assumption that some portion of that .2 constant is accounting for updates to the creep itself, which could be combined when it's doing multiple actions.

Actually, looking at the replay further as well as my stat tracking/when I started getting emails, the npc invader appears to have caused the issue right when it spawned.

The replay: https://screeps.com/a/#!/history/W34S1?t=15902500

There is no data before that, but ticks to live on the npc invader suggests it spawned in the room just before I got the first slew of emails of brokenness, and that happened a while before it ended up on the room border stacked with my creeps coming in to the room.

I've actually had this happen to me twice now, although I'm still not positive on why this happens. As far as I can tell though, the npc invader parks itself on the room border where my creep is trying to enter the room, and once my creep enters the room it ends up on the same tile as the npc invader which I'm assuming causes the error.

Previously when this happened, my scripts would break any time I had vision of that npc invader and was trying to add it to a list. I wasn't able to be online when I started getting emails of script execution terminating and the RangeError, but looking at the replay I could see that a similar situation happened where one of my creeps was entering the same tile as the npc invader.

My guess is that it has something to do with having multiple creeps on the same tile, and a possible fix may be to not allow npc creeps to move back on to exit tiles after they spawn and move off of them.