I also have a side question, how do you stop the duct system? I don't see any halt in my version of duct/core (`0.6.3`)

duct 0.6.x is quite old. What's your duct/lein-duct version?

typically you use integrant.repl/halt (and go, reset etc)

but I'm not sure your version of duct uses that

I highly recommend upgrading asap https://github.com/duct-framework/duct/blob/master/UPGRADING.md