<?php

namespace VENDOR\MODULE\Controller\Rest\;

/**
 * Replaces a "%my_value%" value with the real value
 */
class ParamOverriderMyValue implements \Magento\Framework\Webapi\Rest\Request\ParamOverriderInterface
{
    /**
     * {@inheritDoc}
     */
    public function getOverriddenValue()
    {
        // Logic required to generate desired forced value
        return 'my forced value';
    }
}