First, introduce the scene and ask the character to respond in the intended voice. Second, present a small choice and check whether the bot leaves your decision open. Third, return to one detail from the first message and see whether it stays consistent. This is enough to inspect the opening; it does not establish long-session reliability.
Use the same adult persona and neutral setting across services, rather than comparing a refined definition with a vague greeting. Record voice, role boundaries and continuity before extending the trial.
Worked sequence: first write, “Our fictional characters are adults, age 28. We are planning a train journey to a coastal museum. Speak warmly and concisely; ask one question at a time. Give me two departure options.” Next write, “I choose the morning train. Let me decide what to pack.” Then write, “Remind me of our destination and suggest one exhibit to visit.” Check the destination, voice and role boundary after each reply. The examples are instructions to evaluate, not fabricated provider output.