diff --git a/CHANGELOG.md b/CHANGELOG.md
index ea1fe04c1..59160a53c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@
 * [#2786](https://github.com/ruby-grape/grape/pull/2786): Make route `requirements` and `anchor` explicit keyword arguments and first-class endpoint inputs instead of opaque `route_options` keys - [@ericproulx](https://github.com/ericproulx).
 * [#2788](https://github.com/ruby-grape/grape/pull/2788): Compare the base API instead of `to_s` when refreshing a mounted app - [@ericproulx](https://github.com/ericproulx).
 * [#2796](https://github.com/ruby-grape/grape/pull/2796): Remove `Grape::Util::ReverseStackableValues`, storing rescue handlers in plain per-scope hashes merged over `InheritableSetting#parent` - [@ericproulx](https://github.com/ericproulx).
+* [#2807](https://github.com/ruby-grape/grape/pull/2807): Internalize routing scope flags behind `Grape::Util::InheritableSetting` accessors (`do_not_route_head`, `do_not_route_options`, `do_not_document`, `lint` — `!` writers / `?` readers), and drop the vestigial `namespace_inheritable` hash copy in `Grape::API::Instance`'s route-config collection - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 #### Fixes
diff --git a/UPGRADING.md b/UPGRADING.md
index 9bd07d5df..2b21d69d0 100644
--- a/UPGRADING.md
+++ b/UPGRADING.md
@@ -82,6 +82,10 @@ A route's declared params were previously carried inside the `route_options` bag
 
 Like `params` above, a route's `requirements` and `anchor` were previously carried inside the `route_options` bag. They are now composed into their own endpoint inputs (`Grape::Endpoint::Options` gains `:requirements` and `:anchor` members, and `Grape::Endpoint.new` gains `requirements:` and `anchor:` keywords) and exposed only through the `route.requirements` and `route.anchor` readers. `route.options[:requirements]` and `route.options[:anchor]` now return `nil` — including for a mount's `anchor: false`. Nothing in Grape or grape-swagger read them that way, so this only affects code that reached into the options Hash for these keys directly.
 
+#### Routing scope flags are recorded through `InheritableSetting` accessors
+
+The flags flipped by `do_not_route_head!`, `do_not_route_options!`, `do_not_document!` and `lint!` are now recorded and read through dedicated accessors on `Grape::Util::InheritableSetting` (`!` writers, `?` readers) instead of raw `namespace_inheritable` keys. The `?` readers return `false` (rather than `nil`) when never set; every consumer only used them in boolean context, so behavior is unchanged. The keys' storage is unchanged for now, so `namespace_inheritable[:do_not_route_head]` and friends still return the same values, but they should be considered internal.
+
 ### Upgrading to >= 3.3
 
 #### Minimum required Ruby is now 3.3
diff --git a/lib/grape/api/instance.rb b/lib/grape/api/instance.rb
index c9e39a3ff..458023541 100644
--- a/lib/grape/api/instance.rb
+++ b/lib/grape/api/instance.rb
@@ -154,18 +154,11 @@ def add_head_not_allowed_methods_and_options_methods
         # contain already versioning information when using path versioning.
         all_routes = self.class.endpoints.flat_map(&:routes)
 
-        # Read the settings the helper routes need from a *copy* with the
-        # root-prefix/versioning keys stripped, so adding these routes won't
-        # prepend versioning information again. This used to delete those keys
-        # from the shared class-level settings and restore them in an ensure;
-        # a request served concurrently on another instance during a runtime
-        # recompile could observe the missing keys (e.g. via #cascade?). A
-        # local copy keeps that mutation off the shared object.
-        namespace_inheritable = self.class.inheritable_setting.namespace_inheritable.to_hash.except(*ROOT_PREFIX_VERSIONING_KEYS)
-        collect_route_config_per_pattern(all_routes, namespace_inheritable)
+        collect_route_config_per_pattern(all_routes)
       end
 
-      def collect_route_config_per_pattern(all_routes, namespace_inheritable)
+      def collect_route_config_per_pattern(all_routes)
+        setting = self.class.inheritable_setting
         routes_by_regexp = all_routes.group_by(&:pattern_regexp)
 
         # Build the configuration based on the first endpoint and the collection of methods supported.
@@ -174,18 +167,15 @@ def collect_route_config_per_pattern(all_routes, namespace_inheritable)
 
           last_route = routes.last # Most of the configuration is taken from the last endpoint
           allowed_methods = routes.map(&:request_method)
-          allowed_methods |= [Rack::HEAD] if !namespace_inheritable[:do_not_route_head] && allowed_methods.include?(Rack::GET)
+          allowed_methods |= [Rack::HEAD] if !setting.do_not_route_head? && allowed_methods.include?(Rack::GET)
 
-          allow_header = namespace_inheritable[:do_not_route_options] ? allowed_methods : [Rack::OPTIONS] | allowed_methods
-          last_route.app.options_route_enabled = true unless namespace_inheritable[:do_not_route_options] || allowed_methods.include?(Rack::OPTIONS)
+          allow_header = setting.do_not_route_options? ? allowed_methods : [Rack::OPTIONS] | allowed_methods
+          last_route.app.options_route_enabled = true unless setting.do_not_route_options? || allowed_methods.include?(Rack::OPTIONS)
 
           greedy_route = Grape::Router::GreedyRoute.new(last_route.pattern, endpoint: last_route.app, allow_header:)
           @router.associate_routes(greedy_route)
         end
       end
-
-      ROOT_PREFIX_VERSIONING_KEYS = %i[version version_options root_prefix].freeze
-      private_constant :ROOT_PREFIX_VERSIONING_KEYS
     end
   end
 end
diff --git a/lib/grape/dsl/routing.rb b/lib/grape/dsl/routing.rb
index 20bbc7d07..2e16d1e4c 100644
--- a/lib/grape/dsl/routing.rb
+++ b/lib/grape/dsl/routing.rb
@@ -107,20 +107,20 @@ def build_with(build_with)
 
       # Do not route HEAD requests to GET requests automatically.
       def do_not_route_head!
-        inheritable_setting.namespace_inheritable[:do_not_route_head] = true
+        inheritable_setting.do_not_route_head!
       end
 
       # Do not automatically route OPTIONS.
       def do_not_route_options!
-        inheritable_setting.namespace_inheritable[:do_not_route_options] = true
+        inheritable_setting.do_not_route_options!
       end
 
       def lint!
-        inheritable_setting.namespace_inheritable[:lint] = true
+        inheritable_setting.lint!
       end
 
       def do_not_document!
-        inheritable_setting.namespace_inheritable[:do_not_document] = true
+        inheritable_setting.do_not_document!
       end
 
       def mount(mounts, *opts)
diff --git a/lib/grape/endpoint.rb b/lib/grape/endpoint.rb
index 9502cdc2c..8e74bbd4a 100644
--- a/lib/grape/endpoint.rb
+++ b/lib/grape/endpoint.rb
@@ -124,7 +124,7 @@ def mount_in(router)
       compile!
       routes.each do |route|
         router.append(route.apply(self))
-        next if inheritable_setting.namespace_inheritable[:do_not_route_head] || route.request_method != Rack::GET
+        next if inheritable_setting.do_not_route_head? || route.request_method != Rack::GET
 
         router.append(route.to_head.apply(self))
       end
@@ -422,7 +422,7 @@ def build_response_cookies
     end
 
     def lint?
-      inheritable_setting.namespace_inheritable[:lint] || Grape.config.lint
+      inheritable_setting.lint? || Grape.config.lint
     end
   end
 end
diff --git a/lib/grape/util/inheritable_setting.rb b/lib/grape/util/inheritable_setting.rb
index 912b1f68d..2f85d9919 100644
--- a/lib/grape/util/inheritable_setting.rb
+++ b/lib/grape/util/inheritable_setting.rb
@@ -106,6 +106,43 @@ def namespace_stackable_with_hash(key)
         data.each_with_object({}) { |value, result| result.deep_merge!(value) }
       end
 
+      # Scope flags flipped by the routing DSL's bang methods (see
+      # DSL::Routing#do_not_route_head! and friends; Validations::OneofCollector
+      # also flips +do_not_document!+): once set in a scope they apply to it
+      # and everything nested under it. Readers return false when never set;
+      # the backing store is an internal detail.
+      def do_not_route_head!
+        namespace_inheritable[:do_not_route_head] = true
+      end
+
+      def do_not_route_head?
+        namespace_inheritable[:do_not_route_head] == true
+      end
+
+      def do_not_route_options!
+        namespace_inheritable[:do_not_route_options] = true
+      end
+
+      def do_not_route_options?
+        namespace_inheritable[:do_not_route_options] == true
+      end
+
+      def do_not_document!
+        namespace_inheritable[:do_not_document] = true
+      end
+
+      def do_not_document?
+        namespace_inheritable[:do_not_document] == true
+      end
+
+      def lint!
+        namespace_inheritable[:lint] = true
+      end
+
+      def lint?
+        namespace_inheritable[:lint] == true
+      end
+
       # Rescue-handler maps registered by +rescue_from+, keyed by exception
       # class and merged so a nested scope's handler wins. Record them with
       # #add_rescue_handlers; the backing store is an internal detail.
diff --git a/lib/grape/validations/oneof_collector.rb b/lib/grape/validations/oneof_collector.rb
index 84fa32d08..2023f07f1 100644
--- a/lib/grape/validations/oneof_collector.rb
+++ b/lib/grape/validations/oneof_collector.rb
@@ -12,7 +12,7 @@ class OneofCollector
 
       def initialize
         @inheritable_setting = Grape::Util::InheritableSetting.new
-        @inheritable_setting.namespace_inheritable[:do_not_document] = true
+        @inheritable_setting.do_not_document!
       end
 
       def configuration
diff --git a/lib/grape/validations/params_documentation.rb b/lib/grape/validations/params_documentation.rb
index a17e80b0d..72d3b0111 100644
--- a/lib/grape/validations/params_documentation.rb
+++ b/lib/grape/validations/params_documentation.rb
@@ -6,7 +6,7 @@ module Validations
     # +ValidationsSpec+; never mutates the user's validations hash.
     module ParamsDocumentation
       def document_params(attrs, spec)
-        return if @api.inheritable_setting.namespace_inheritable[:do_not_document]
+        return if @api.inheritable_setting.do_not_document?
 
         documented_attrs = attrs.to_h do |name|
           [full_name(name), extract_details(spec)]
diff --git a/spec/grape/dsl/routing_spec.rb b/spec/grape/dsl/routing_spec.rb
index 57afe0c47..81cf482e2 100644
--- a/spec/grape/dsl/routing_spec.rb
+++ b/spec/grape/dsl/routing_spec.rb
@@ -58,14 +58,14 @@ class << self
   describe '.do_not_route_head!' do
     it 'sets do not route head option' do
       subject.do_not_route_head!
-      expect(subject.inheritable_setting.namespace_inheritable[:do_not_route_head]).to be(true)
+      expect(subject.inheritable_setting.do_not_route_head?).to be(true)
     end
   end
 
   describe '.do_not_route_options!' do
     it 'sets do not route options option' do
       subject.do_not_route_options!
-      expect(subject.inheritable_setting.namespace_inheritable[:do_not_route_options]).to be(true)
+      expect(subject.inheritable_setting.do_not_route_options?).to be(true)
     end
   end
 
diff --git a/spec/grape/validations/params_documentation_spec.rb b/spec/grape/validations/params_documentation_spec.rb
index b6e1fdcab..a0b1174a5 100644
--- a/spec/grape/validations/params_documentation_spec.rb
+++ b/spec/grape/validations/params_documentation_spec.rb
@@ -64,7 +64,7 @@ def spec_for(validations)
       end
 
       before do
-        api_double.inheritable_setting.namespace_inheritable[:do_not_document] = true
+        api_double.inheritable_setting.do_not_document!
       end
 
       it 'does not store any documented params' do