Building Claude Code: how Anthropic uses skills

Lessons from building Claude Code: How we use skills

Anthropic shared lessons from hundreds of active skills inside Claude Code, grouping them into nine uses and covering how to write, distribute and measure them. A skill is a folder of instructions, scripts and resources. Write down common errors, load reference files on demand, reuse helper scripts, and phrase the description as a trigger condition. Small teams can share skills through a repo; at larger scale an internal plugin marketplace works, with a PreToolUse hook logging usage to find skills that under-trigger.

Why it matters: Anthropic sorts internal skill practice into nine uses and distills a team skill library from error logs, on-demand file reads and script reuse.