The environment stops being your friend
SWE-bench hands you a codebase. WebArena hands you a website. τ-bench hands you a user who wants help. A buying committee hands you nothing.
When an agent negotiates or sells, its counterpart is strategically non-cooperative: it holds private information, has goals only partly aligned with the agent’s, and reveals value only in response to earned trust. Success is not one verifiable end state but a trajectory of earned commitments — a quantified pain, a meeting with the person who controls budget, a price held under pressure. The paper argues existing benchmarks sidestep three difficulties this regime creates.
Partial information, gated disclosure
The environment must withhold facts until the agent earns them through the right kind of question. A benchmark that hands over the answer on request can’t measure discovery skill — only discovery effort.
Process credit, not just outcome
A deal can close for the wrong reasons (an unforced discount) or fail despite excellent execution. A scalar win/loss reward conflates skill with luck — and rewards value-destroying shortcuts.
Methodology attribution
Does a selling methodology actually improve outcomes? Isolating its effect means holding model, scenario, and counterpart fixed while varying only the method — a control almost never built into agentic benchmarks.
Cooperative or static environment · single verifiable end state · scalar reward · one deterministic interlocutor you can overfit.
Adversarial stochastic committee · trajectory of earned sub-goals · evidence-cited scorecard · buyer re-sampled every seed.