Monitoring driven development

Context: There was this company who was doing all the agile things looking from the outside, however from the inside... It was a SaaS product, and they were incredibly immature in terms of running a production system - lots of trivial knowledge, lots of reliance on that one guy. We walked through the "marketecture", and go through every line - "what would happen if this arrow didn't work?". And things broke down very quickly. And then I thought about it from TDD background - how would we develop software differently if we were to think about how are we gonna monitor software.

---