Thanks for these great answers!
The seconds question is mostly curiosity. I often find myself grinding up against Tinderbox's rough edges, like this one, and I want to know if it's a limit in Tinderbox or in my understanding.
I'm very glad that Tinderbox supports finer-than-minute granularity generally, since I use timestamps, obtained from $Created, as UUIDs in some of my Tinderbox documents, and I often create more than one note per minute. (Given that Tinderbox does support fine time granularity, it strikes me as strange that today would be rounded to the minute, since this seems like it would require more work rather than less, but anyway....)
The agent-priority question does have a real-world problem behind it: I often find that for debugging it's useful to have an action that only runs manually. This is especially true for multi-stage agent cascades, where one agent narrows the query results of another. I typically hack it by turning an agent on and off, using boolean guards, or use an edict for this. I was kind of hoping for low-priority agents to act like edicts, with update cycles so infrequent that for debugging purposes you can consider them to be manually run, so I was surprised to see the low-priority agent updating regularly.
Would you see any use for an agent priority level that means "manual-update only"? This strikes me as useful.