Overview
A more capable harness is not automatically a better harness. Adding tools increases action space and security exposure. Adding memory can preserve useful knowledge but can also preserve stale or incorrect rules. Allowing longer runs can complete larger tasks but also gives errors more time to compound. Tight permissions improve containment but can interrupt autonomous execution.
The useful design question is therefore not, "How many capabilities can this agent have?" It is, "Which capabilities, context, and permissions are necessary for this class of work, and how will the system verify that each step remains on course?"