diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 8d6203b99d..a38c4ecc0b 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -504,37 +504,45 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
   end
 
   SCAN_SEARCHABILITY_RE = /\[searchability:(public|followers|reactors|private)\]/
+  SCAN_SEARCHABILITY_FEDIBIRD_RE = /searchable_by_(all_users|followers_only|reacted_users_only|nobody)/
 
   def searchability
-    searchability = searchability_from_audience
-
-    if searchability.nil?
-      note = @account&.note
-      return nil if note.blank?
-
-      searchability_bio = note.scan(SCAN_SEARCHABILITY_RE).first
-      return nil unless searchability_bio
-
-      searchability = searchability_bio[0]
-      return nil if searchability.nil?
-
-      searchability = :public  if searchability == 'public'
-      searchability = :private if searchability == 'followers'
-      searchability = :limited if searchability == 'private'
-      searchability = :direct  if searchability == 'reactors'
-    end
+    searchability = searchability_from_audience || searchability_from_bio || (marked_as_misskey_searchability? ? :public : nil)
+    return nil if searchability.nil?
 
     visibility = visibility_from_audience_with_silence
 
     if searchability == visibility || searchability == :limited || searchability == :direct
       searchability
-    elsif [:public, :unlisted, :private].include?(searchability) && [:public, :public_unlisted, :unlisted, :login, :private].include?(visibility)
+    elsif [:public, :unlisted, :private].include?(searchability) && [:private].include?(visibility)
       :private
     else
       :direct
     end
   end
 
+  def searchability_from_bio
+    note = @account&.note
+    return nil if note.blank?
+
+    searchability_bio = note.scan(SCAN_SEARCHABILITY_RE).first || note.scan(SCAN_SEARCHABILITY_FEDIBIRD_RE).first
+    return nil unless searchability_bio
+
+    searchability = searchability_bio[0]
+    return nil if searchability.nil?
+
+    searchability = :public  if %w(public all_users).include?(searchability)
+    searchability = :private if %w(followers followers_only).include?(searchability)
+    searchability = :limited if %w(private reacted_users_only).include?(searchability)
+    searchability = :direct  if %w(reactors nobody).include?(searchability)
+
+    searchability
+  end
+
+  def marked_as_misskey_searchability?
+    @marked_as_misskey_searchability ||= DomainBlock.detect_invalid_subscription?(@account.domain)
+  end
+
   def visibility_from_audience
     if audience_to.any? { |to| ActivityPub::TagManager.instance.public_collection?(to) }
       :public
diff --git a/app/models/domain_block.rb b/app/models/domain_block.rb
index 36998957e0..b05fa19476 100644
--- a/app/models/domain_block.rb
+++ b/app/models/domain_block.rb
@@ -110,6 +110,10 @@ class DomainBlock < ApplicationRecord
       !!rule_for(domain)&.reject_new_follow?
     end
 
+    def detect_invalid_subscription?(domain)
+      !!rule_for(domain)&.detect_invalid_subscription?
+    end
+
     def reject_reports?(domain)
       !!rule_for(domain)&.reject_reports?
     end
diff --git a/app/services/activitypub/process_account_service.rb b/app/services/activitypub/process_account_service.rb
index 61a2d2e9d1..9c2bda08fa 100644
--- a/app/services/activitypub/process_account_service.rb
+++ b/app/services/activitypub/process_account_service.rb
@@ -8,6 +8,8 @@ class ActivityPub::ProcessAccountService < BaseService
 
   SUBDOMAINS_RATELIMIT = 10
   DISCOVERIES_PER_REQUEST = 400
+  SCAN_SEARCHABILITY_RE = /\[searchability:(public|followers|reactors|private)\]/
+  SCAN_SEARCHABILITY_FEDIBIRD_RE = /searchable_by_(all_users|followers_only|reacted_users_only|nobody)/
 
   # Should be called with confirmed valid JSON
   # and WebFinger-resolved username and domain
@@ -252,7 +254,12 @@ class ActivityPub::ProcessAccountService < BaseService
   end
 
   def searchability_from_audience
-    return :private if audience_searchable_by.nil?
+    if audience_searchable_by.nil?
+      bio = searchability_from_bio
+      return bio unless bio.nil?
+
+      return marked_as_misskey_searchability? ? :public : :private
+    end
 
     if audience_searchable_by.any? { |uri| ActivityPub::TagManager.instance.public_collection?(uri) }
       :public
@@ -263,6 +270,28 @@ class ActivityPub::ProcessAccountService < BaseService
     end
   end
 
+  def searchability_from_bio
+    note = @json['summary'] || ''
+    return nil if note.blank?
+
+    searchability_bio = note.scan(SCAN_SEARCHABILITY_RE).first || note.scan(SCAN_SEARCHABILITY_FEDIBIRD_RE).first
+    return nil unless searchability_bio
+
+    searchability = searchability_bio[0]
+    return nil if searchability.nil?
+
+    searchability = :public  if %w(public all_users).include?(searchability)
+    searchability = :private if %w(followers followers_only).include?(searchability)
+    searchability = :limited if %w(private reacted_users_only).include?(searchability)
+    searchability = :direct  if %w(reactors nobody).include?(searchability)
+
+    searchability
+  end
+
+  def marked_as_misskey_searchability?
+    domain_block&.detect_invalid_subscription
+  end
+
   def subscribable_by
     return nil if @json['subscribableBy'].nil?