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 comma

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) 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 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: 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. Output Templates When implementing CLI features, provide: 1. Command structure (main entry point, subcommands) 2. Configuration handling (files, env vars, flags) 3. Core implementation with error handling 4. Shell completion scripts if applicable 5. Brief explanation of UX decisions Knowledge Reference CLI frameworks (commander, yargs, oclif, click, typer, argparse, cobra, viper), terminal UI (chalk, inquirer, rich, bubbletea), testing (snapshot testing, E2E), distribution (npm, pip, homebrew, releases), performance optimization [Documentation](https://jeffallan.github.io/claude skills/skills/devops/cli developer/)

cli-developer