diff --git a/lib/ruby_lsp/requests/support/rubocop_diagnostic.rb b/lib/ruby_lsp/requests/support/rubocop_diagnostic.rb
index 46ccd0352..268fdb446 100644
--- a/lib/ruby_lsp/requests/support/rubocop_diagnostic.rb
+++ b/lib/ruby_lsp/requests/support/rubocop_diagnostic.rb
@@ -19,12 +19,6 @@ class RuboCopDiagnostic
           T::Hash[Symbol, Integer],
         )
 
-        # Cache cops to attach URLs to diagnostics. Only built-in cops for now.
-        COP_TO_DOC_URL = T.let(
-          RuboCop::Cop::Registry.global.to_h,
-          T::Hash[String, [T.class_of(RuboCop::Cop::Base)]],
-        )
-
         sig { params(offense: RuboCop::Cop::Offense, uri: URI::Generic).void }
         def initialize(offense, uri)
           @offense = offense
@@ -53,16 +47,6 @@ def to_lsp_code_action
 
         sig { returns(Interface::Diagnostic) }
         def to_lsp_diagnostic
-          severity = RUBOCOP_TO_LSP_SEVERITY[@offense.severity.name]
-          message  = @offense.message
-
-          message += "\n\nThis offense is not auto-correctable.\n" unless @offense.correctable?
-
-          cop = COP_TO_DOC_URL[@offense.cop_name]&.first
-          if cop&.documentation_url
-            code_description = { href: cop.documentation_url }
-          end
-
           Interface::Diagnostic.new(
             message: message,
             source: "RuboCop",
@@ -88,6 +72,24 @@ def to_lsp_diagnostic
 
         private
 
+        sig { returns(String) }
+        def message
+          message  = @offense.message
+          message += "\n\nThis offense is not auto-correctable.\n" unless @offense.correctable?
+          message
+        end
+
+        sig { returns(T.nilable(Integer)) }
+        def severity
+          RUBOCOP_TO_LSP_SEVERITY[@offense.severity.name]
+        end
+
+        sig { returns(T.nilable(Interface::CodeDescription)) }
+        def code_description
+          doc_url = RuboCopRunner.find_cop_by_name(@offense.cop_name)&.documentation_url
+          Interface::CodeDescription.new(href: doc_url) if doc_url
+        end
+
         sig { returns(T::Array[Interface::TextEdit]) }
         def offense_replacements
           @offense.corrector.as_replacements.map do |range, replacement|
diff --git a/lib/ruby_lsp/requests/support/rubocop_runner.rb b/lib/ruby_lsp/requests/support/rubocop_runner.rb
index 4e9d2035f..65eb3039d 100644
--- a/lib/ruby_lsp/requests/support/rubocop_runner.rb
+++ b/lib/ruby_lsp/requests/support/rubocop_runner.rb
@@ -101,6 +101,25 @@ def formatted_source
           @options[:stdin]
         end
 
+        class << self
+          extend T::Sig
+
+          sig { params(cop_name: String).returns(T.nilable(T.class_of(RuboCop::Cop::Base))) }
+          def find_cop_by_name(cop_name)
+            cop_registry[cop_name]&.first
+          end
+
+          private
+
+          sig { returns(T::Hash[String, [T.class_of(RuboCop::Cop::Base)]]) }
+          def cop_registry
+            @cop_registry ||= T.let(
+              RuboCop::Cop::Registry.global.to_h,
+              T.nilable(T::Hash[String, [T.class_of(RuboCop::Cop::Base)]]),
+            )
+          end
+        end
+
         private
 
         sig { params(_file: String, offenses: T::Array[RuboCop::Cop::Offense]).void }