Function start_steps 

pub fn start_steps(running: bool, stale: bool) -> StartSteps

What lev must do to reach “a daemon on the current build is running”.

A daemon on an older build is restarted rather than reused. It cannot pick up new code, and the alternative - talking to it anyway - means a lev that was just rebuilt silently drives the previous build’s engine. The restart is safe because the daemon reloads its persisted agents on startup, so in-flight runs survive the swap.

stale is only meaningful when running; a build marker left by a daemon that has since exited says nothing about what is about to be spawned.