I reproduce and repair bounded bugs in Python, JavaScript, SQL, or API workflows using a client-owned branch, test tenant, emulator, duplicate base, or redacted fixture. Delivery includes the exact change, reproducible tests, unresolved assumptions, and rollback or removal notes. I begin with a failing example and acceptance test, isolate the root cause, make the smallest defensible change, and verify behavior before handoff. AI-assisted tools may support diagnosis or coding; I review and test the final result.