cli-developer

Jeffallan/claude-skillsCommand LineReview advisedSnapshot 26181079bb97

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Summary

Use when building CLI tools, implementing argument parsing, or adding interactive prompts. Invoke for parsing flags and subcommands, displaying progress bars and spinners, generating bash/zsh/fish completion scripts, CLI design, shell completions, and cross-platform terminal applications using commander, click, typer, or cobra.

SKILL.md

CLI Developer

Core Workflow

Analyze UX — Identify user workflows, command hierarchy, common tasks. Validate by listing all commands and their expected --help output before writing code.
Design commands — Plan subcommands, flags, arguments, configuration. Confirm flag naming is consistent and no existing signatures are broken.
Implement — Build with the appropriate CLI framework for the language (see Reference Guide below). After wiring up commands, run <cli> --help to verify help text renders correctly and <cli> --version to confirm version output.
Polish — Add completions, help text, error messages, progress indicators. Verify TTY detection for color output and graceful SIGINT handling.
Test — Run cross-platform smoke tests; benchmark startup time (target: <50ms).

Reference Guide

Load detailed guidance based on context:

Topic	Reference	Load When
Design Patterns	`references/design-patterns.md`	Subcommands, flags, config, architecture
Node.js CLIs	`references/node-cli.md`	commander, yargs, inquirer, chalk
Python CLIs	`references/python-cli.md`	click, typer, argparse, rich
Go CLIs	`references/go-cli.md`	cobra, viper, bubbletea
UX Patterns	`references/ux-patterns.md`

#!/usr/bin/env node
// npm install commander
const { program } = require('commander');

program
  .name('mytool')
  .description('Example CLI')
  .version('1.0.0');

program
  .command('greet <name>')
  .description('Greet a user')
  .option('-l, --loud', 'uppercase the greeting')
  .action((name, opts) => {
    const msg = `Hello, ${name}!`;
    console.log(opts.loud ? msg.toUpperCase() : msg);
  });

program.parse();

Block on synchronous I/O unnecessarily — use async reads or stream processing instead.
Print to stdout when output will be piped — write logs/diagnostics to stderr.

Use colors when output is not a TTY — detect before applying color:

// Node.js
const useColor = process.stdout.isTTY;

# Python
import sys
use_color = sys.stdout.isatty()

// Go
import "golang.org/x/term"
useColor := term.IsTerminal(int(os.Stdout.Fd()))

Break existing command signatures — treat flag/subcommand renames as breaking changes.
Require interactive input in CI/CD environments — always provide non-interactive fallbacks via flags or env vars.
Hardcode paths or platform-specific logic — use os.homedir() / os.UserHomeDir() / Path.home() instead.
Ship without shell completions — all three frameworks above have built-in completion generation.

cli-developer

Summary

SKILL.md

CLI Developer

Core Workflow

Reference Guide

Quick-Start Example

Node.js (commander)

Constraints

MUST DO

MUST NOT DO

Output Templates

Knowledge Reference

Related skills