What causes "npx requires a command argument" in rtk-ai/rtk?

Pass the command you want to run, e.g. `rtk npx vitest run` or `rtk npx tsc --noEmit`

npx requires a command argument

Error message

npx requires a command argument

What it means

`rtk npx` proxies npm's `npx`, which needs a package/binary plus command to execute. When the args vector after `npx` is empty, src/main.rs:2765 bails with `anyhow::bail!` because there is nothing to route to the specialized filters (tsc, eslint, etc.) or the passthrough executor.

Solutions

Pass the command you want to run, e.g. `rtk npx vitest run` or `rtk npx tsc --noEmit`
Check that any variable interpolated into the command is non-empty before invoking
Use plain `npx --help` (outside rtk) if you only wanted npx usage information

Example fix

// before (PKG empty)
rtk npx $PKG
// after
rtk npx vitest run

Defensive patterns

Strategy: validation

Validate before calling

// shell: require a non-empty command before invoking rtk npx
if [ -z "${1:-}" ]; then echo "usage: rtk npx <command> [args...]" >&2; exit 1; fi
rtk npx "$@"

Try / catch

// Rust caller
if args.is_empty() {
    eprintln!("rtk npx requires a command, e.g. rtk npx tsc --noEmit");
    std::process::exit(2);
}
rtk_npx(&args)?;

Prevention

Always quote/verify interpolated variables before `rtk npx $VAR`
Invoke rtk npx with at least a binary name plus args
Add usage text in wrapper scripts when arg count is 0

When it happens

Trigger: Running `rtk npx` with no further arguments (e.g. typing `rtk npx` alone, or a script building the command from a variable that ended up empty).

Common situations: A shell variable holding the package name is unset (`rtk npx $PKG`); a fat command alias lost its arguments; forgetting that unlike bare `npx` (which prints help), rtk requires an explicit command.

Understand the failure class

Background: "no subcommand specified" and "... is required": CLI errors when a required argument is missing — this error's family across 13 libraries.

Related errors

AI-assisted analysis of rtk-ai/rtk@0924356b4c (2026-09-19). Data as JSON: /api/errors/c61543dd919a2e7e. Report an issue: GitHub.

Appendix: source

Thrown at src/main.rs:2765

            write_rules,
            min_confidence,
            min_occurrences,
        } => {
            learn::run(
                project,
                all,
                since,
                format,
                write_rules,
                min_confidence,
                min_occurrences,
            )?;
            0
        }

        Commands::Npx { args } => {
            if args.is_empty() {
                anyhow::bail!("npx requires a command argument");
            }

            // Intelligent routing: delegate to specialized filters
            match args[0].as_str() {
                "tsc" | "typescript" => tsc_cmd::run(Some("npx"), &args[1..], cli.verbose)?,
                "eslint" => lint_cmd::run(Some("npx"), &args, cli.verbose)?,
                "prisma" => {
                    // Route to prisma_cmd based on subcommand
                    if args.len() > 1 {
                        let prisma_args: Vec<String> = args[2..].to_vec();
                        match args[1].as_str() {
                            "generate" => prisma_cmd::run(
                                prisma_cmd::PrismaCommand::Generate,
                                &prisma_args,
                                cli.verbose,
                            )?,
                            "db" if args.len() > 2 && args[2] == "push" => prisma_cmd::run(
                                prisma_cmd::PrismaCommand::DbPush,

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