Skill or Subagent? The 30-Second Rule Most Claude Code Devs Still Get Wrong

Two Claude Code primitives. Two very different jobs. Here's the rule I use to pick between them. Most devs still confuse these Almost every Claude Code setup I review has the same bug: subagents doing the work of skills, and skills being skipped where they'd actually help. The two primitives look similar from the outside. They do very different jobs. The rule Skill = knowledge you reuse. Subagent = capability you delegate. Everything else is examples. Skill: durable knowledge the model reads every time A skill is a folder in ~/.claude/skills/ / with a SKILL.md and any ing files.