Trying to lock a API route behind authentication, having problems authenticating from my web app

import { createFunctionPrecondition } from '@sapphire/decorators';
import { HttpCodes, ApiResponse, ApiRequest } from '@sapphire/plugin-api';

export const authenticated = () =>
    createFunctionPrecondition(
        (request: ApiRequest) => Boolean(request.auth?.token),
        (_request: ApiRequest, response: ApiResponse) => response.error(HttpCodes.Unauthorized)
    );

        const settingsResponse = await fetch(`${process.env.DISCORD_BOT_URL}/api/guilds/${guildId}/config`, {
            method: 'GET',
            headers: {
                'Content-Type': 'application/json'
            },
            // Send the token in the auth property as expected by the decorator (I thought?)
            credentials: 'include',
            // @ts-ignore - Adding auth property to fetch options
            auth: {
                token: session.accessToken
            }
        });