diff --git a/AGENTS.md b/AGENTS.md
index a14ae0cfa5..99a3e191e6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -143,7 +143,7 @@ This codebase (Rails 8.1)
 | `SectorsTaggable` | Enforces a single primary sector for sector-tagged owners |
 | `TagFilterable` | Scope-based filtering by tag names |
 | `Trendable` | Trending metrics tracking |
-| `UserStampable` | Stamps `updated_by_id` from `Current.user` on every write (no-op without the column) |
+| `UserStampable` | Stamps `created_by_id`/`updated_by_id` from `Current.user` (no-op without the columns) |
 | `WindowsTypeFilterable` | Filter by WindowsType association |
 
 ## Controllers
diff --git a/app/controllers/comments_controller.rb b/app/controllers/comments_controller.rb
index 93928cb6d8..11f5fb0edf 100644
--- a/app/controllers/comments_controller.rb
+++ b/app/controllers/comments_controller.rb
@@ -13,7 +13,6 @@ def index
   def create
     authorize!
     @comment = @commentable.comments.build(comment_params)
-    @comment.created_by = current_user
     @comment.updated_by = current_user
 
     if @comment.save
diff --git a/app/controllers/community_news_controller.rb b/app/controllers/community_news_controller.rb
index 10ce42cfe0..433d67dc00 100644
--- a/app/controllers/community_news_controller.rb
+++ b/app/controllers/community_news_controller.rb
@@ -61,7 +61,6 @@ def edit
 
   def create
     @community_news = CommunityNews.new(community_news_params)
-    @community_news.created_by = current_user
     authorize! @community_news
 
     success = false
diff --git a/app/controllers/event_registrations_controller.rb b/app/controllers/event_registrations_controller.rb
index 3dccb72f18..fdec9e354b 100644
--- a/app/controllers/event_registrations_controller.rb
+++ b/app/controllers/event_registrations_controller.rb
@@ -79,8 +79,6 @@ def create
   def update
     authorize! @event_registration
     @event_registration.assign_attributes(event_registration_update_params)
-    @event_registration.comments.select(&:new_record?).each { |c| c.created_by = current_user; c.updated_by = current_user }
-    @event_registration.comments.select { |c| c.persisted? && c.body_changed? }.each { |c| c.updated_by = current_user }
 
     # Inline-logged notifications are addressed to the registrant.
     recipient_email = @event_registration.registrant&.preferred_email.presence || "n/a"
diff --git a/app/controllers/events/registrations_controller.rb b/app/controllers/events/registrations_controller.rb
index 082ddf4779..b1c24ee508 100644
--- a/app/controllers/events/registrations_controller.rb
+++ b/app/controllers/events/registrations_controller.rb
@@ -170,7 +170,6 @@ def create_person_for_current_user
         first_name: current_user.first_name,
         last_name: current_user.last_name,
         email: current_user.email,
-        created_by: current_user,
         updated_by: current_user
       )
       current_user.update!(person: person)
diff --git a/app/controllers/events_controller.rb b/app/controllers/events_controller.rb
index daa1c6052b..9064a58bb3 100644
--- a/app/controllers/events_controller.rb
+++ b/app/controllers/events_controller.rb
@@ -315,7 +315,6 @@ def send_reminder
   def create
     authorize!
     @event = Event.new(event_params)
-    @event.created_by ||= current_user
 
     success = false
 
diff --git a/app/controllers/grants_controller.rb b/app/controllers/grants_controller.rb
index d2ed0a6a94..33b1cce3eb 100644
--- a/app/controllers/grants_controller.rb
+++ b/app/controllers/grants_controller.rb
@@ -48,7 +48,6 @@ def edit
 
   def create
     @grant = Grant.new(grant_params)
-    @grant.created_by = current_user
     @grant.updated_by = current_user
     authorize! @grant
 
diff --git a/app/controllers/organizations_controller.rb b/app/controllers/organizations_controller.rb
index a5c7c1e17d..4d6eddcd19 100644
--- a/app/controllers/organizations_controller.rb
+++ b/app/controllers/organizations_controller.rb
@@ -127,8 +127,6 @@ def create
   def update
     authorize! @organization
     @organization.assign_attributes(organization_params)
-    @organization.comments.select(&:new_record?).each { |c| c.created_by = current_user; c.updated_by = current_user }
-    @organization.comments.select { |c| c.persisted? && c.body_changed? }.each { |c| c.updated_by = current_user }
 
     if @organization.save
       assign_associations(@organization) if params.dig(:organization, :category_ids)
diff --git a/app/controllers/people_controller.rb b/app/controllers/people_controller.rb
index 1928782486..7c8a19ec8f 100644
--- a/app/controllers/people_controller.rb
+++ b/app/controllers/people_controller.rb
@@ -224,8 +224,6 @@ def update
     attrs = person_params
     reject_locked_license_changes!(attrs)
     @person.assign_attributes(attrs)
-    @person.comments.select(&:new_record?).each { |c| c.created_by = current_user; c.updated_by = current_user }
-    @person.comments.select { |c| c.persisted? && c.body_changed? }.each { |c| c.updated_by = current_user }
 
     # Inline-logged notifications are addressed to the person.
     recipient_email = @person.preferred_email.presence || "n/a"
diff --git a/app/controllers/resources_controller.rb b/app/controllers/resources_controller.rb
index deb644e4d7..b213861531 100644
--- a/app/controllers/resources_controller.rb
+++ b/app/controllers/resources_controller.rb
@@ -103,7 +103,6 @@ def create
   def update
     @resource = Resource.find(params[:id])
     authorize! @resource
-    @resource.created_by ||= current_user
     success = false
 
     Resource.transaction do
@@ -192,7 +191,7 @@ def resource_params
   def load_forms
     form = @resource.form
     if form
-      @user_form = Report.new(created_by: current_user, owner: @resource)
+      @user_form = Report.new(owner: @resource)
       form.form_fields.where(status: 1).order(:position).each do |field|
         @user_form.report_form_field_answers.build(form_field: field)
       end
diff --git a/app/controllers/scholarships_controller.rb b/app/controllers/scholarships_controller.rb
index 7cdda55792..51aa7a4911 100644
--- a/app/controllers/scholarships_controller.rb
+++ b/app/controllers/scholarships_controller.rb
@@ -82,7 +82,6 @@ def update
     authorize! @scholarship
 
     @scholarship.assign_attributes(scholarship_params)
-    attribute_comment_authorship
 
     # Inline-logged notifications are addressed to the scholarship recipient.
     recipient_email = @scholarship.recipient&.preferred_email.presence || "n/a"
@@ -212,16 +211,4 @@ def scholarship_params
       notifications_attributes: [ :id, :channel, :sender_id, :email_subject, :email_body_text, :noticeable_type, :noticeable_id, :_destroy ]
     )
   end
-
-  # Stamp authorship on comments edited through the scholarship form: author + editor
-  # on new ones, editor on existing ones whose body changed.
-  def attribute_comment_authorship
-    @scholarship.comments.select(&:new_record?).each do |c|
-      c.created_by = current_user
-      c.updated_by = current_user
-    end
-    @scholarship.comments.select { |c| c.persisted? && c.body_changed? }.each do |c|
-      c.updated_by = current_user
-    end
-  end
 end
diff --git a/app/controllers/stories_controller.rb b/app/controllers/stories_controller.rb
index 34b618fabf..eac0333344 100644
--- a/app/controllers/stories_controller.rb
+++ b/app/controllers/stories_controller.rb
@@ -63,7 +63,6 @@ def edit
 
   def create
     @story = Story.new(story_params.except(:category_ids, :sector_ids))
-    @story.created_by = current_user
     authorize! @story
 
     success = false
diff --git a/app/controllers/story_ideas_controller.rb b/app/controllers/story_ideas_controller.rb
index 3d40639a1a..f43e339133 100644
--- a/app/controllers/story_ideas_controller.rb
+++ b/app/controllers/story_ideas_controller.rb
@@ -33,7 +33,6 @@ def edit
 
   def create
     @story_idea = StoryIdea.new(story_idea_params.except(:category_ids, :sector_ids))
-    @story_idea.created_by = current_user
     @story_idea.updated_by = current_user
     authorize! @story_idea
 
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 574ad17dc2..38a11cb90c 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -99,7 +99,6 @@ def create
     # assign person
     person_id = params[:person_id].presence || params.dig(:user, :person_id).presence
     @user.person = Person.find(person_id) if person_id
-    @user.created_by = current_user
     @user.updated_by = current_user
 
     if @user.save
@@ -134,8 +133,6 @@ def update
 
     @user.assign_attributes(user_params.except(:password, :password_confirmation))
     @user.updated_by = current_user
-    @user.comments.select(&:new_record?).each { |c| c.created_by = current_user; c.updated_by = current_user }
-    @user.comments.select { |c| c.persisted? && c.body_changed? }.each { |c| c.updated_by = current_user }
 
     # Suppress Devise's automatic reconfirmation email so the interstitial can control it
     @user.skip_confirmation_notification!
diff --git a/app/controllers/workshops_controller.rb b/app/controllers/workshops_controller.rb
index 0650ef5286..de316651bb 100644
--- a/app/controllers/workshops_controller.rb
+++ b/app/controllers/workshops_controller.rb
@@ -82,7 +82,7 @@ def new
       @workshop = WorkshopFromIdeaService.new(@workshop_idea, user: current_user).call
       authorize! @workshop
     else
-      @workshop = Workshop.new(created_by: current_user)
+      @workshop = Workshop.new
       authorize! @workshop
     end
     set_form_variables
@@ -156,8 +156,6 @@ def update
     success = false
 
     @workshop.assign_attributes(workshop_params)
-    @workshop.comments.select(&:new_record?).each { |c| c.created_by = current_user; c.updated_by = current_user }
-    @workshop.comments.select { |c| c.persisted? && c.body_changed? }.each { |c| c.updated_by = current_user }
 
     Workshop.transaction do
       if @workshop.save
diff --git a/app/models/concerns/user_stampable.rb b/app/models/concerns/user_stampable.rb
index ddc587e1bf..4798be5d02 100644
--- a/app/models/concerns/user_stampable.rb
+++ b/app/models/concerns/user_stampable.rb
@@ -1,25 +1,41 @@
 module UserStampable
   extend ActiveSupport::Concern
 
-  # Stamps updated_by_id from Current.user on every write, so the last editor is
-  # recorded on the record itself. (created_by_id is set at create time by the
-  # controllers; only updated_by_id was going unset on updates.) Included on
-  # ApplicationRecord; the guard makes it a no-op for tables without the column. Runs
-  # on before_validation so it satisfies a required belongs_to :updated_by before the
-  # presence check.
+  # Stamps created_by_id / updated_by_id from Current.user so attribution lives on the
+  # record itself instead of being assigned by hand in every controller. Included on
+  # ApplicationRecord; the guards make it a no-op for tables without the columns. Runs
+  # on before_validation so it satisfies a required belongs_to before the presence
+  # check.
   included do
-    before_validation :stamp_updated_by
+    before_validation :stamp_user_columns
   end
 
   private
 
-  def stamp_updated_by
+  def stamp_user_columns
     user = Current.user
     return unless user
+
+    stamp_created_by(user)
+    stamp_updated_by(user)
+  end
+
+  # Only at creation, and always the authenticated actor — created_by is not a
+  # user-supplied value, so a mass-assigned created_by_id must not override it. A
+  # later editor never reaches this (guarded on new_record?), so it can't claim it.
+  def stamp_created_by(user)
+    return unless new_record? && has_attribute?(:created_by_id)
+
+    self.created_by_id = user.id
+  end
+
+  def stamp_updated_by(user)
     return unless has_attribute?(:updated_by_id)
 
     # Skip when the caller set updated_by_id explicitly (respect it), and when nothing
     # else changed (don't turn a no-op save into a write / spurious update event).
+    # A save whose only changes are to associations leaves the record itself unchanged,
+    # so those paths still assign updated_by by hand.
     return if updated_by_id_changed?
     return unless new_record? || changed?
 
diff --git a/spec/models/concerns/user_stampable_spec.rb b/spec/models/concerns/user_stampable_spec.rb
index e0fb3ee44b..f0383bcf48 100644
--- a/spec/models/concerns/user_stampable_spec.rb
+++ b/spec/models/concerns/user_stampable_spec.rb
@@ -1,7 +1,7 @@
 require "rails_helper"
 
 RSpec.describe UserStampable, type: :model do
-  # Banner carries both stamp columns and a required belongs_to :created_by.
+  # Banner carries both stamp columns, each a required belongs_to.
   let(:creator) { create(:user) }
   let(:editor)  { create(:user) }
 
@@ -10,26 +10,27 @@ def with_current(user, &block)
   end
 
   describe "on create" do
-    it "stamps updated_by from Current.user" do
-      banner = with_current(creator) { Banner.create!(content: "Hi", show: true, created_by: creator) }
+    it "stamps created_by and updated_by from Current.user" do
+      banner = with_current(creator) { Banner.create!(content: "Hi", show: true) }
 
+      expect(banner.created_by).to eq(creator)
       expect(banner.updated_by).to eq(creator)
     end
 
-    it "satisfies a required belongs_to :updated_by without an explicit assignment" do
-      expect { with_current(creator) { Banner.create!(content: "Hi", show: true, created_by: creator) } }
+    it "satisfies required belongs_to stamps without an explicit assignment" do
+      expect { with_current(creator) { Banner.create!(content: "Hi", show: true) } }
         .not_to raise_error
     end
 
-    it "leaves created_by to the caller" do
+    it "forces created_by to Current.user, ignoring a mass-assigned value" do
       banner = with_current(creator) { Banner.create!(content: "Hi", show: true, created_by: editor) }
 
-      expect(banner.created_by).to eq(editor)
+      expect(banner.created_by).to eq(creator)
     end
   end
 
   describe "on update" do
-    let!(:banner) { with_current(creator) { Banner.create!(content: "Hi", show: true, created_by: creator) } }
+    let!(:banner) { with_current(creator) { Banner.create!(content: "Hi", show: true) } }
 
     it "stamps updated_by with the current editor without touching created_by" do
       with_current(editor) { banner.update!(content: "Edited") }
@@ -58,6 +59,7 @@ def with_current(user, &block)
         Banner.create!(content: "Hi", show: true, created_by: creator, updated_by: creator)
       end
 
+      expect(banner.created_by).to eq(creator)
       expect(banner.updated_by).to eq(creator)
     end
   end