From f87772ef41392442d51c776fd910de65f7472b24 Mon Sep 17 00:00:00 2001
From: Javier Romero Castro <jrcastro9515@gmail.com>
Date: Thu, 11 May 2023 10:07:38 +0200
Subject: [PATCH] authentication: document that info has to return external id

* closes https://github.com/inveniosoftware/invenio-app-rdm/issues/2186
---
 docs/customize/authentication.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/customize/authentication.md b/docs/customize/authentication.md
index 2db0312d..680b1e81 100644
--- a/docs/customize/authentication.md
+++ b/docs/customize/authentication.md
@@ -577,6 +577,10 @@ handlers = _keycloak_helper.get_handlers()
 handlers["signup_handler"]["info_serializer"] = custom_info_serializer
 ```
 
+!!! info "Mandatory external id"
+    When customizing an info endpoint, it is mandatory for a field to provide an external ID. This field must be named `external_id`.
+
+
 ### New OAuth plugins
 
 If you need to implement your own OAuth plugin to enable integration with your OAuth provider,