can1357/oh-my-pi · error · Error

missing value for ${arg}

Error message

missing value for ${arg}

What it means

The CLI arg parser's take() helper returns an option's value: either an inline `--flag=value` value or the next argv entry. When the flag is last in argv with no inline value, the next token is undefined and this error is thrown naming the flag.

Source

Thrown at packages/metaharness/src/tb/cli.ts:122

		vmonUrl: "http://xeon.internal:17970",
		vmonToken: "",
		list: false,
		help: false,
	};
	let modelsSpecified = false;

	for (let i = 0; i < argv.length; i++) {
		let arg = argv[i];
		let inlineValue: string | null = null;
		const equals = arg.startsWith("--") ? arg.indexOf("=") : -1;
		if (equals !== -1) {
			inlineValue = arg.slice(equals + 1);
			arg = arg.slice(0, equals);
		}
		const take = (): string => {
			if (inlineValue !== null) return inlineValue;
			const value = argv[++i];
			if (value === undefined) throw new Error(`missing value for ${arg}`);
			return value;
		};
		switch (arg) {
			case "-m":
			case "--model":
				if (!modelsSpecified) {
					config.models = [];
					modelsSpecified = true;
				}
				config.models.push(take());
				break;
			case "--dataset":
				config.dataset = take();
				break;
			case "-i":
			case "--include":
				config.include.push(take());
				break;

View on GitHub (pinned to 9690622007)

Solutions

1. Append the missing value after the flag (e.g. `tb --model anthropic/claude-sonnet-4`)
2. Or use the inline form `--model=anthropic/claude-sonnet-4`
3. In scripts, quote variables so empty values are not dropped: tb --model "$MODEL"

Example fix

// before
$ tb --model
// after
$ tb --model anthropic/claude-sonnet-4

function hasValue(argv: string[], flag: string): boolean {
  const i = argv.indexOf(flag);
  return i === -1 || (i + 1 < argv.length && !argv[i + 1].startsWith("-")) || flag.includes("=");
}

try {
  config = parseArgs(process.argv.slice(2));
} catch (err) {
  if (String(err.message).startsWith("missing value for")) {
    console.error(`${err.message}; usage: tb --model <provider/model>`);
    process.exit(2);
  }
  throw err;
}

When it happens

Trigger: Invoking e.g. `tb --model` (or -m, --gateway-url, --openrouter-variant, etc.) as the final argument with no following token and no `=` form.

Common situations: Truncated copy-paste of a command line; shell history trimming; scripts building argv where the value variable is empty and gets dropped by word splitting (e.g. unquoted empty shell variable).

Related errors

• missing value for ${flag}
• unknown option: ${arg}
• missing operand
• Expected --${name} to be a positive integer, got ${value}
• Cache flags require --cache

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/94e632e11583fcbf. Report an issue: GitHub.