rust-domain-cli

name	rust-domain-cli
description	Rust CLI application development. Activates for command-line tool design, argument parsing with clap, TUI frameworks, terminal I/O, progress bars, and CLI UX patterns.

Rust CLI Domain Skill

Stack Selection

Component	Recommended	Alternative
Arg parsing	clap (derive)	argh (minimal)
Config files	config + serde	figment
TUI	ratatui	cursive
Colors	owo-colors	colored
Progress bars	indicatif	—
Tables	comfy-table	tabled
Dialogs/prompts	dialoguer	inquire
Logging	tracing + tracing-subscriber	env_logger

Clap Derive Pattern

use clap::{Parser, Subcommand};

#[derive(Parser)]
#[command(name = "my-tool", version, about = "Tool description")]
struct Cli {
    #[command(subcommand)]
    command: Commands,

    /// Enable verbose output
    #[arg(short, long, global = true)]
    verbose: bool,
}

#[derive(Subcommand)]
enum Commands {
    /// Initialize a new project
    Init {
        /// Project name
        #[arg(value_name = "NAME")]
        name: String,
    },
    /// Run the tool
    Run {
        /// Config file path
        #[arg(short, long, default_value = "config.toml")]
        config: PathBuf,
    },
}

CLI UX Patterns

• Use stderr for progress/status, stdout for data output (pipe-friendly)
• Support --json flag for machine-readable output
• Use exit codes: 0 = success, 1 = runtime error, 2 = usage error
• Respect NO_COLOR env var and --no-color flag
• Show help when invoked with no arguments (if no default action)
• Use anyhow for errors displayed to users (good formatting)

Error Display for CLI

fn main() {
    if let Err(err) = run() {
        eprintln!("error: {err:#}");
        std::process::exit(1);
    }
}

Config File Loading Order

1. Built-in defaults
2. System config (/etc/my-tool/config.toml)
3. User config (~/.config/my-tool/config.toml)
4. Project config (./.my-tool.toml)
5. Environment variables (MY_TOOL_*)
6. Command-line arguments (highest priority)