Mendral co-founder here. What happens at PostHog is not uncommon. While building Mendral, we talked to hundreds of team and they all have a similar situation. Initially they come to us to make their CI pipelines faster. But as the agent dives in, the urgency becomes keeping all pipelines reliable. It comes from growing a code base with a test suite. Of course it has to change eventually: splitting the test suite, running specific part of the CI depending on the code, etc... But the situation described in the article is widespread with a product that grows quickly.