I am using Github Provider of next-auth package for signIn in a NextJs 14 Project. This is my authConfig:

import Github from "next-auth/providers/github";
import NextAuth, { NextAuthOptions } from "next-auth";
import User from "@/models/User";

const authOptions: NextAuthOptions = {
    providers: [
        Github({
            clientId: process.env.GITHUB_ID ?? "",
            clientSecret: process.env.GITHUB_SECRET ?? "",
        }),
    ],
    callbacks: {
        async signIn({ user, account, profile, email, credentials }): Promise<boolean> {
            ......
        },
        async jwt({ token, user, account, session }) {

            if (account) {
                token.provider = account.provider;
            }

            if(account && account.provider == 'github') {
                const dbUser = await User.findOne({ github_id: account.providerAccountId }).exec();
                token.user_id = dbUser._id.toString();
            }

            return token;
        },
        async session({ session, token, user }) {

            session.user.user_id = token.user_id as string;
            session.user.isAdmin = true;

            return session;
        },

    },
    session: {
        strategy: "jwt", // default
    },
}


export {
    authOptions
}

The issue is when fetch session in server component or api route using getServerSession() the isAdmin and user_id fields are missing:

const session = await getServerSession();
console.log(session);

// {
//  user: {
//    name: 'username',
//    email: undefined,
//    image: 'image.png'
//  }
}

What I need is upadte the session with field user_id which is the mongoDB _id of user with matching github user id.

Above code update the session and i can see updated session at api endpoint: api/auth/session.

{
  "user": {
    "name": "username",
    "image": "image.png",
    "user_id": "66d54f8d0828ddbf7c0a1256",
    "isAdmin": true
  },
  "expires": "2025-08-02T07:17:33.804Z"
}

I need above result when called from getServerSession.