How would you answer an interview scenario involving Tokens, context windows, and truncation?

For an interview scenario involving Tokens, context windows, and truncation, I would first clarify the business goal, scale, constraints, and the failure or quality attribute the interviewer wants to explore. Tokens are the units processed by language models, and the context window limits how much prompt and generated content can be considered in one request. In this scenario, for a long-running chat application, explain how you would preserve conversation continuity without sending the entire history on every request. I would then explain the main alternatives and tradeoffs, identify likely failure modes, and describe how I would validate the solution through testing, observability, security controls, and recovery or rollback planning.