yet-another-agent-harness: Skill for Claude Code

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