writing-skillslisted

# Writing Skills ## Overview Writing skills is Test-Driven Development applied to process documentation. You write pressure scenarios (test cases), watch a baseline agent fail without the skill (RED), write the minimal skill that fixes those failures (GREEN), and close the loopholes testing exposes (REFACTOR). **Core principle:** if you didn't watch an agent fail without the skill, you don't know whether the skill teaches the right thing. Required background: megapowers:test-driven-development defines the RED-GREEN-REFACTOR cycle this skill adapts. For current portable OpenAI and Anthropic guidance, see authoring-best-practices.md. For the research on phrasing that lands, see effective-phrasing.md. When editing an existing skill down, de-prescription-rubric.md is the trim standard: it says what to remove, what to keep, and what never to touch. ## What a Skill Is A reusable reference for a proven technique, pattern, or tool. Not a narrative about how you solved a problem once. Create one when the technique was not obvious to you, applies beyond one project, and will be needed again. Skip one-off fixes, practices well documented elsewhere, project-specific conventions (those belong in the project's instructions file), and mechanical constraints (automate those with validation; save documentation for judgment calls). Structure: a SKILL.md, plus supporting files only for reusable tools or reference material too heavy to inline. The body covers an overview with the core pri