Practical Guide to Evaluating and Testing Claude Code Skills
Skills are everywhere. Since Anthropic launched Claude Code , the ecosystem has exploded with custom "Skills"—directories of instructions and scripts that teach Claude how to handle specific domains. But there is a problem: almost nobody is testing them. Most developers "vibe-check" their skills with a few manual prompts, see a good response, and ship it. You wouldn’t ship a TypeScript library without a test suite, so why ship a Skill without an evaluation? This is a practical guide to fixing that. What Are Claude Code Skills? Agent Skills are folders that augment Claude's capabilities without retraining the model. They follow a progressive disclosure pattern, meaning Claude only loads the full instructions when it thinks they are relevant. At a minimum, a skill requires a SKILL.md file in .claude/skills/ : --- name: ts-zod-architect description: Use this skill when the user wants to define data models or API schema...