Agent harness techniques tested: which framework designs raise scores and which just raise cost

现在的 Agent Harness 越来越复杂，哪些技巧在跑分里真正管用

Controlled experiments from Surge AI and FireFlash show coding agents can improve through deeper single-model reasoning, test and goal-check gates, and a reworked terminal pipeline. In Surge AI's run, Compound Engineering lifted cost to 8x baseline while the score moved only from 31.1 to 32.9. Claude Opus 5.5 with higher thinking settings reached 42.4 at 3.5x baseline cost.

Why it matters: The two teams break down the cost and payoff of agent harness techniques, comparing multi-agent collaboration, deeper single-model thinking and terminal pipeline changes.