There is a silent war happening in your organization. The Finance team demands lower cloud bills, Product demands faster features, and Reliability demands zero downtime. Caught in the middle is the Developer, expected to satisfy everyone manually, creating friction and cognitive load. To succeed, we must make efficiency an invisible platform capability. This talk explores a strategy to automate this balance using open source tools. We will implement a dual feedback loop: first, validating performance inside the pipeline to block regressions before they merge; second, analyzing production data to auto-tune workloads based on reality, not guesses. I will share a reference architecture and a live demo showing a pipeline that automatically rejects inefficient code, followed by an autonomous loop that opens a Pull Request to right-size resources based on real-world runtime behavior.