Reading a skill is the cheap part. The work it drives is where the tokens and the time go - every search, file read, retry and wrong turn the agent takes along the way. A good skill makes that work predictable: fewer wrong turns, and the same result tomorrow as today.

This article walks through how I plan and write skills, with a release-notes skill as the running example, and how to test them with tools like skillgrade.

Coding agents forget everything between sessions, and the bigger the codebase grows, the more they have to rediscover before they can do anything useful.

This article covers spec-driven development as a whole - why agents need specs, the frameworks worth starting with, and how my own setup evolved from homegrown commands to OpenSpec and beads.