What causes "invalid model ${model}; expected provider/model" in can1357/oh-my-pi?

Use full provider/model form, e.g. anthropic/claude-sonnet-4

invalid model ${model}; expected provider/model

Error message

invalid model ${model}; expected provider/model

What it means

Each --model value must be of the form provider/model: it must contain a '/' that is neither the first character nor the last. This error is thrown for values violating that shape.

Source

Thrown at packages/metaharness/src/tb/cli.ts:204

				config.vmonToken = take();
				break;
			case "--list":
				config.list = true;
				break;
			case "-h":
			case "--help":
				config.help = true;
				break;
			default:
				throw new Error(`unknown option: ${arg}`);
		}
	}

	if (config.help) return config;
	if (config.models.length === 0) throw new Error("at least one --model is required");
	for (const model of config.models) {
		const slash = model.indexOf("/");
		if (slash <= 0 || slash === model.length - 1) throw new Error(`invalid model ${model}; expected provider/model`);
	}
	for (const [flag, value] of [
		["--attempts", config.attempts],
		["--concurrency", config.concurrency],
		["--epochs", config.epochs],
	] as const) {
		if (!Number.isInteger(value) || value < 1) throw new Error(`${flag} must be a positive integer`);
	}
	if (config.budget !== null && (!Number.isFinite(config.budget) || config.budget < 0)) {
		throw new Error("--budget must be a non-negative number");
	}
	return config;
}

class Semaphore {
	#available: number;
	#queue: Array<() => void> = [];

View on GitHub (pinned to 9690622007)

Solutions

Use full provider/model form, e.g. anthropic/claude-sonnet-4
Remove leading/trailing slashes from the value
Check for empty values caused by unquoted shell variables

Example fix

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

Defensive patterns

Strategy: validation

Validate before calling

const validModel = (m: string) => {
  const s = m.indexOf("/");
  return s > 0 && s < m.length - 1;
};
if (!models.every(validModel)) throw new Error("every model must be provider/model");

Try / catch

try {
  config = parseArgs(args);
} catch (err) {
  if (String(err.message).startsWith("invalid model")) {
    console.error(`${err.message} — use e.g. anthropic/claude-sonnet-4`);
    process.exit(2);
  }
  throw err;
}

Prevention

Always prefix bare model names with their provider id
Trim model strings from env/config before passing
Validate model lists at script boundaries

When it happens

Trigger: Passing a bare model name ('claude-sonnet-4'), a leading-slash ('/gpt-4o'), a trailing slash ('openrouter/'), or an empty string via --model=.

Common situations: Model IDs from docs that omit the provider prefix; joining a list where the last element is empty; Windows-style paths or typos introducing stray slashes; using an OpenRouter variant-only suffix instead of the full id.

Related errors

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/53f0e3d6fe96a674. Report an issue: GitHub.