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The skill worth building first

Checking Claude's work currently depends on you remembering to ask. Skip it once and a broken refactor ships. A verification skill removes that dependency: it fires on its own when the task matches its description, walks the same steps every time, and reports what it found.

Build one for the queries project. There is no test suite here, so the command that tells you whether the code still works is the TypeScript compiler: npx tsc --noEmit reads every file, reports any errors it finds, and writes nothing.

This exercise is part of the course

Claude Code in Action

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Exercise instructions

  • Start Claude Code with claude.
  • Ask Claude to create a skill at .claude/skills/verify-changes/SKILL.md, with a description saying it runs after edits to source files.
  • Have the procedure run npx tsc --noEmit, read the diff, confirm no check was weakened just to pass, and report pass or fail with the evidence.
  • Type /exit to exit Claude Code.

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