τ²-bench is a benchmark for conversational agents operating in dual-control environments, where both the agent and a simulated user can take actions within a shared system. Tasks are grounded in realistic service and troubleshooting domains—including telecom/account management, device and connectivity issues, billing and plan changes, and general customer support workflows. To succeed, agents must not only use tools and follow policies, but also coordinate with the user, guide their actions, ask clarifying questions, and recover from misunderstandings.