Win without breaking something.
Every change that improves one metric can quietly harm another. Guardrails are the numbers you promise not to damage.
Primary metric ↑ while guardrails hold
The Pairing
Customer satisfaction
Are people happier, or just faster?
Errors and incidents
Did we introduce instability?
Support contacts
Did we move work onto the support team?
Revenue quality
Did we attract customers who won't pay?
Move the needle. Mind the fences.