run was handed something that is not one script file.

Its own failure rather than a reused ScriptNotFound because the two say different things: this one is "you wanted the other verb", and its message says which. target is rendered rather than echoed raw so an array or an options object reads as itself.

import { NotAScriptFile } from './run.ts';

NotAScriptFile({ target: 'tests/', reason: 'a directory' }).data.reason; // 'a directory'
NotAScriptFile({ target: 'tests/', reason: 'a directory' }).message.includes('test('); // true