Why Claude Code Skills Don't Trigger (And How to Fix Them in 2026)

The core problem with Claude Code skills is a token budget overflow that silently drops your skill descriptions before Claude ever reads them. If you have built skills, tested them manually, and then watched Claude ignore them in real sessions — you are not doing it wrong. You are hitting a documented architectural limitation that most developers never find. This article covers the full picture: how Claude Code skills actually work under the hood, the three root causes of missed triggers, and the reliable fixes — including when to use Anthropic's new Skill Creator tool to measure and iterate. What Is a Claude Code Skill, Actually? A Claude Code skill is a SKILL.md file in .claude/skills/<name>/ that Claude loads dynamically when it decides the skill is relevant to your request. It is not a plugin, not a system prompt injection, and not a function call. It is closer to a context-gated instruction block — Claude reads the description, decides if it matches the current task, and only then