What job must be done?
Belief
Tools.
The right tool saves thought. It carries embedded knowledge, narrows the job, and lets humans and AI agents spend attention where judgment still matters.
Which tool already knows part of the work?
Who should use it: human, AI, or both?
What thought, time, context, or risk does it remove?
What output shows the tool made the job easier to do well?
Choose the smallest capable tool.
A weak tool makes the agent think too hard. An oversized tool adds ceremony. A good tool stores the routine part of the job so the next decision can focus on values, risk, proof, and timing.
For agent work, that connects directly to skills: a skill is useful only when it places the right load on the human, the model, and the system.