Reason Less, Verify More: Deterministic Gates Catch a Silent Policy-Violation Failure in Tool-Using Agents

arXiv·medium signal

'Reason Less, Verify More' (arXiv:2607.07405, July 8, 2026) identifies a 'silent wrong-state' failure mode in tool-using agents: a well-formed but policy-forbidden call (cancel a booking, change a passenger count, act on a claim without verification) that neither the tool nor the agent's self-report flags. In the tau-squared-bench airline domain, 78% of a budget agent's failures are these silent policy violations with no tool error — and the fix is not more reasoning but cheap, read-only deterministic gates that check the state transition against domain policy before the write commits. For builders: wrap high-stakes tool calls in explicit precondition checks rather than trusting the model to self-police.