GPT-5.6 Built Feasible Trip Plans in 46.2% of Solvable Tasks
Photo: TokenPost
An AI travel planner can access travel-time estimates and still produce a schedule that cannot be completed. In TREK, a July 2026 benchmark of 15 agents, GPT-5.6 produced fully feasible plans for 46.2% of tasks with a valid solution, showing the difficulty of turning travel information into a workable itinerary. TREK tested 800 trip-planning tasks. Of those, 533 had a valid solution and 267 were designed to be impossible. Agents could use tools, including one that calculated travel time between locations, and had to satisfy constraints involving budgets, trip length, business hours and travelers’ unstated preferences.
Source: TokenPost
