Source coding

Source coding is the theory of compression: how few bits it takes to represent a message without losing what it means. Shannon's result is that the floor is the source's entropy. Squeeze to there and you have removed all the redundancy; squeeze further and you start dropping real content.

The idea carries over to how we build. Writing one tight, reusable spec is source coding for a workflow: capture the essential instruction once, instead of paying to re-explain it in full every single time.