Are there established best practices for "engineering" prompts systematically, rather than through trial-and-error?

Editing prompts is like playing whack-a-mole: once you clear an edge case, a new problem pops up elsewhere. I'd really like to be able to say, "this new prompt performs 20% better across all our test cases".

Because I haven't found a better way, I am building https://github.com/typpo/promptfoo, a CLI that outputs a matrix view for quickly comparing outputs across multiple prompts, variables, and models. Good luck to everyone else out there tuning prompts :)