diff --git a/docs/topics/settings.rst b/docs/topics/settings.rst
index d3fe6bbe2..3006fb8b1 100644
--- a/docs/topics/settings.rst
+++ b/docs/topics/settings.rst
@@ -115,8 +115,10 @@ arguments <spiderargs>` or other logic:
         @classmethod
         def from_crawler(cls, crawler, *args, **kwargs):
             spider = super().from_crawler(crawler, *args, **kwargs)
-            if "value" in kwargs:
-                spider.settings.set("SOME_SETTING", kwargs["value"], priority="spider")
+            if "some_argument" in kwargs:
+                spider.settings.set(
+                    "SOME_SETTING", kwargs["some_argument"], priority="spider"
+                )
             return spider
 
 3. Project settings module
diff --git a/docs/topics/spiders.rst b/docs/topics/spiders.rst
index d9cbbe35a..3197daf65 100644
--- a/docs/topics/spiders.rst
+++ b/docs/topics/spiders.rst
@@ -138,10 +138,11 @@ scrapy.Spider
 
        .. versionchanged:: VERSION
 
-           The settings in ``crawler.settings`` can now be modified, which is
-           handy if you want to modify them based on arguments. As a
-           consequence, these settings aren't the final values as they can be
-           modified later by e.g. :ref:`add-ons <topics-addons>`.
+           The settings in ``crawler.settings`` can now be modified in this
+           method, which is handy if you want to modify them based on
+           arguments. As a consequence, these settings aren't the final values
+           as they can be modified later by e.g. :ref:`add-ons
+           <topics-addons>`. The settings become final when the spider starts.
 
        :param crawler: crawler to which the spider will be bound
        :type crawler: :class:`~scrapy.crawler.Crawler` instance