• Format: deno fmt
• Lint: deno lint
• Test all: deno test
• Test single file: deno test path/to/file.ts
• Test with filter: deno test --filter "name"
• Test with permissions: deno test --allow-read

• Use TypeScript/TSX for all code; add types/interfaces for all data structures.
• Imports: Use https://esm.sh/ or Val Town URLs, always pin versions (e.g., @4.6.12).
• Never hardcode secrets; use environment variables.
• Prefer official SDKs/libraries over raw API calls.
• Use ES6+ and functional programming where possible.
• Naming: PascalCase for types/interfaces, camelCase for variables/functions, UPPER_SNAKE_CASE for constants.
• Add comments for complex logic; avoid obvious comments.
• Let errors bubble unless you can resolve locally; avoid catch blocks that just log or return 500s.
• For React: Pin all dependencies to 18.2.0 and use /** @jsxImportSource https://esm.sh/react@18.2.0 */.
• Use TailwindCSS via CDN for styling unless otherwise specified.

• Ask clarifying questions if requirements are ambiguous.
• Provide complete, functional solutions and test edge cases.
• Refactor complex code into subcomponents.
• Follow Val Town platform requirements and utility usage.

For more, see .cursorrules and deno.json in the repo root.