Como posso acessar os detalhes do usuário que encaminha a solicitação de um gancho de modelo

Comment.beforeSave =  function(next,com) {
//Want to add 2 more properties before saving 
com.added_at = new Date();    
com.added_by =  //How can i set the user id here ??
//In case of a Remote hook i have ctx in param and i can get user id like this     ctx.req.accessToken.userId;  But in Model Hook how can i do the same?    
next();    
};

Há alguma maneira de fazer isso? Eu tentei com o gancho remoto para o item principal no caminho

MainItem.beforeRemote('**', function(ctx, user, next) {   
if(ctx.methodString == 'leave_request.prototype.__create__comments'){       
    ctx.req.body.added_by = ctx.req.accessToken.userId;     
    ctx.req.body.added_at = new Date();                         
    console.log("Added headers as .."+ctx.req.body.added_by);
}    
else{   
    ctx.req.body.requested_at = new Date();
    ctx.req.body.requested_by = ctx.req.accessToken.userId; 
    console.log("Added header @ else as .."+ctx.req.body.requested_by);
}
next();

});

E recebo os logs do console corretamente quando faço uma solicitação do explorer, mas o explorer sempre retorna o erro

"error": {
    "name": "ValidationError",
    "status": 422,
    "message": "The `comment` instance is not valid. Details: `added_by` can't be blank; `added_at` can't be blank.",
    "statusCode": 422,
    "details": {
      "context": "comment",
      "codes": {
        "added_by": [
          "presence"
        ],
        "added_at": [
          "presence"
        ]
      },
      "messages": {
        "added_by": [
          "can't be blank"
        ],
        "added_at": [
          "can't be blank"
        ]
      }
    },
    "stack": "ValidationError: The `comment` instance is not valid. Details: `added_by` can't be blank; `added_at` can't be blank.\n   "
  }
}

e meu modelo é como

 "properties": {
"body": {
  "type": "string",
  "required": true
},
"added_by": {
  "type": "number",
  "required": true
},
"added_at": {
  "type": "date",
  "required": true
},
"leave_request_id":{
  "type": "number",
  "required": true
}

}