Migrating a large legacy test suite is not a code-generation problem. It is a confidence problem.
An agent can translate an old test into modern syntax very quickly. The difficult question is whether it preserved the behavior-and how you can prove that across hundreds or thousands of tests without manually supervising every generated change.
I built an agent harness to solve that problem. You point it at a specification, and it works through every test hands-free: it plans the work, writes the migration, explores the live application when needed, runs verification, records evidence, and moves on only when the evidence is complete.
The model does the work inside the loop. The harness owns everything between the steps: scope, retries, verification, evidence, and the final decision.
A model may propose a migration. It never gets to declare that migration complete.
