deno-cliffy-cli_skill

Overview

This skill helps you build structured command-line tools in Deno using the Cliffy command framework. It focuses on typed options, built-in help text, subcommands, and a small project layout that scales from single-file tools to multi-command CLIs. The guidance covers wiring commands, integrating deno.json tasks, and handling heavy or npm dependencies safely.

How this skill works

You create a Command instance from @cliffy/command, register commands and options, and call parse(Deno.args) to run. For multi-command projects, place individual command handlers in a commands/ directory and import or lazy-load them from the entry point. Use deno.json to centralize imports, map npm packages, and define per-command task invocations with appropriate permission flags.

When to use it

• Creating a new Deno CLI with subcommands and typed options
• Refactoring an existing script into a maintainable multi-command tool
• Coordinating deno.json tasks with CLI subcommands and permission scoping
• Adding heavy dependencies (Playwright, Puppeteer) that should not load on every run
• Using npm packages in Deno that require filesystem assets or node-style modules

Best practices

• Keep each command in its own file under commands/ and export a single async function
• Lazy-import heavy or side-effecting dependencies inside action handlers to avoid unnecessary startup costs
• Define imports and npm mappings in deno.json and set nodeModulesDir: "auto" when packages read their own files
• Scope permissions per deno task (avoid --allow-all unless needed) and pass extra CLI flags after -- in deno task invocations
• Document command options and defaults so auto-generated help is useful and consistent

Example use cases

• A developer tool with build, test, and deploy subcommands wired from commands/ files
• A dotfiles manager that applies or removes configurations with per-command permissions
• A web-scraping command that lazy-loads Playwright only when the scrape subcommand runs
• A templating CLI that uses an npm handlebars package and requires nodeModulesDir to read partials
• deno.json tasks that run specific commands with restricted permission flags for CI