Keep skill descriptions short: they load every turn

Agent skills look free because the body only loads when used. But each skill's name and description stays in context every turn, whether or not the skill fires. Twenty skills with 60-word descriptions is over a thousand tokens of constant overhead.

Quick fix: rewrite each description as one sentence saying when to use it, and move the how-to detail into the skill body. Then weigh the whole set to see what your skills cost before the first prompt.