The phrase "didst to a T" means "did perfectly" or "did exactly as required." Synonyms for this phrase might include words like executed flawlessly, performed immaculately, complied precisely, or completed faultlessly. Each of these expressions captures the sense of having accomplished a task without error or deviation, and conveys the idea of carrying out a task with great skill, accuracy, and attention to detail. Other synonyms might include executed flawlessly, accomplished with aplomb, or executed with precision, each of which would be more or less interchangeable with "didst to a T" in context.