import os

def check_env(config):
    """
    Validates required environment variables from config.
    Returns: list of (bool, str) - (Success, Message)
    """
    required_vars = config.get("required_env", [])
    if not required_vars:
        return [(True, "No required environment variables specified")]

    results = []
    missing_vars = []
    for var in required_vars:
        if not os.environ.get(var):
            missing_vars.append(var)
    
    if not missing_vars:
        return [(True, "All required environment variables are set")]
    else:
        return [(False, f"Missing environment variables: {', '.join(missing_vars)}")]
