Rails Testing on Autopilot: Building an Agent That Writes What Developers Won't | Mistral AI

In most large Rails monoliths, organizations prioritize writing new features over writing tests for them. Over time, more and more code goes untested, forcing teams to spend more time debugging painful bugs. We built an autonomous agent that closes that gap. It reads Rails source files, generates or improves RSpec tests, validates them against style rules and coverage targets, and runs inside a CI/CD pipeline with no human intervention. To operate on codebases at this scale, it runs in parallel: multiple instances working on different files simultaneously.