• Dev server: pnpm dev (requires Ruby for markdown caching)
• Build: pnpm build
• Test: pnpm test (runs Vitest in watch mode)
• Run single test: pnpm vitest run <file-path> or pnpm vitest <file-path> (watch mode)
• All tests (CI): pnpm ci (runs all linters, tests, and build)
• Lint: pnpm eslint:check or pnpm prettier:check
• Format: pnpm format (runs both ESLint and Prettier fixes)

• Package manager: pnpm (v8.15.4+)
• Framework: Astro with TypeScript (strict mode), Tailwind CSS
• Imports: Use ~/ alias for src/ directory; Prettier organizes imports automatically
• Types: Use Zod schemas for runtime validation (see SheetFrontmatter.ts); TypeScript strict mode enabled
• Naming: camelCase for variables/functions, PascalCase for components/types
• Error handling: Distinguish operational (expected) vs unexpected errors; return error objects for operational errors
• Testing: Vitest with globals enabled; use it.each() for repeated test cases; prefer object constants over helper functions

Consult @_docs/writing-guidelines.md for formatting *.md files.