cli-developer Checked

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.

CLI Developer

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.

CLI Developer

Core Workflow

1. **Analyze UX** — Identify user workflows, command hierarchy, common tasks. Validate by listing all commands and their expected --help output before writing code.

2. **Design commands** — Plan subcommands, flags, arguments, configuration. Confirm flag naming is consistent and no existing signatures are broken.

3. **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.

4. **Polish** — Add completions, help text, error messages, progress indicators. Verify TTY detection for color output and graceful SIGINT handling.

5. **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 | Progress bars, colors, help text |

Quick-Start Example

### Node.js (commander)

#!/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();

For Python (click/typer) and Go (cobra) quick-start examples, see references/python-cli.md and references/go-cli.md.

Constraints

### MUST DO

• Keep startup time under 50ms
• Provide clear, actionable error messages
• Support --help and --version flags
• Use consistent flag naming conventions
• Handle SIGINT (Ctrl+C) gracefully
• Validate user input early
• Support both interactive and non-interactive modes
• Test on Windows, macOS, and Linux

### MUST NOT DO