Anikesh Parashar

Model routing for multi-turn agents is studied at the user-turn boundary, where a router picks one model for the whole turn before it runs. At a matched offloading rate of roughly a fifth of turns, a router that reads session history passes 28.3% of SheetCopilot tasks against 25.0% for the same router seeing only the current request, a 3.3-point gap, while staying within one point of always using the expensive model. A closed-form cache analysis finds downward switches repay their cache cost in about two calls, while upward switches do not break even under the evaluated conditions.

Model routing for multi-turn agents is studied at the user-turn boundary, where a router picks one model for the whole turn before it runs. At a matched offloading rate of roughly a fifth of turns, a router that reads session history passes 28.3% of SheetCopilot tasks against 25.0% for the same router seeing only the current request, a 3.3-point gap, while staying within one point of always using the expensive model. A closed-form cache analysis finds downward switches repay their cache cost in about two calls, while upward switches do not break even under the evaluated conditions.