Theme – requires a dependency “magento/framework” cannot be found

I’ve begun working on a theme for Magento 2. I’m new to this so go easy.
I’ve been following along with the documentation Create a Storefront Theme | Commerce Frontend Development and I want to add an additional dependency via composer.

However if try composer require mindplay/php-vite for example composer throws an error

Root composer.json requires magento/framework, it could not be found in any version, there may be a typo in the package name.

This strikes me as odd as blank/luma and the docs reference magento/framework as a requirement for a theme in composer.json.

Is there a private registry or something I need to add as there is no magento/framework on Packagist.

Am I missing something?

{
    "name": "oliware/theme-frontend-bumblebee",
    "description": "N/A",
    "type": "magento2-theme",
    "license": [
        "OSL-3.0",
        "AFL-3.0"
    ],
    "config": {
        "sort-packages": true
    },
    "version": "0.0.2-alpha",
    "require": {
        "php": "~8.1.0||~8.2.0||~8.3.0",
        "magento/framework": "103.0.*"
    },
    "autoload": {
        "files": [
            "registration.php"
        ]
    }
}

It’s worth noting I am working with a git cloned version of the magento2 repo and developing the theme that way.