The conclusions:

> Planning improves success at additional cost for weaker models but mainly reduces cost, with small decreases in success rate, for stronger models.

> Predefined tools raise success rates for models with weak bash control, whereas bash-only yields higher success at lower cost for bash-capable models, most clearly on shell-centric task types.

> context management extends execution trajectories without substantially altering agent behavior and is most beneficial under tight context budgets

> planning sustains the trajectories of models that abandon tasks too early and trims repeated verification in models that verify too long

> structured tools support models with limited shell proficiency, while bash-only enables capable models to combine multiple code modifications in a single tool call

Seems fairly intuitive to me, based on feeling. But also fairly kind of obvious; bash-only tooling has higher success for bash-capable models, compared to using predefined tools for models that aren't good at bash? Yeah... They all seem a bit "duh" to me. The final piece of the conclusion is agreeable regardless of how they arrived at it though:

> Harness design is thus a conditional systems problem in which each component should be selected for the target model, task type, and resource budget rather than adopted as a default.

I think lots of people treat the harness/model/prompts combo as interchangeable, but in my experience the quality and efficiently depends heavily on the combo of the harness/model, and using the harness + model made by the same lab, has vastly better experience compared to more "general purpose" (for the lack of a better term) harnesses. Most likely because they use their own traces when training future model iterations.