Function build_cache_note 

pub fn build_cache_note() -> &'static str

What a seat that may build is told about the shared build cache.

Spliced into every node prompt (in [crate::graph::wave]) when the run’s config declares a CARGO_TARGET_DIR — which is also the directory the verify commands build into. The text is stable so tests can assert on it; the value of the variable is not spelled out because the seat reads it from its own environment, and a prompt that hardcodes a path would go stale the moment the config moves the cache.

The fund-transfer reality it exists to prevent: an implementer that builds with its own CARGO_TARGET_DIR (or lets cargo create a fresh target/ in the worktree) is compiling a second copy of the world that nobody prunes, on a machine that has already had that exact failure once.