diff --git a/plugins/commands/serve/mappers.rb b/plugins/commands/serve/mappers.rb
index 94f768b51..a724e711b 100644
--- a/plugins/commands/serve/mappers.rb
+++ b/plugins/commands/serve/mappers.rb
@@ -223,3 +223,4 @@ require Vagrant.source_root.join("plugins/commands/serve/mappers/target.rb").to_
 require Vagrant.source_root.join("plugins/commands/serve/mappers/target_index.rb").to_s
 require Vagrant.source_root.join("plugins/commands/serve/mappers/terminal.rb").to_s
 require Vagrant.source_root.join("plugins/commands/serve/mappers/command.rb").to_s
+require Vagrant.source_root.join("plugins/commands/serve/mappers/capability.rb").to_s
diff --git a/plugins/commands/serve/mappers/capability.rb b/plugins/commands/serve/mappers/capability.rb
new file mode 100644
index 000000000..da755e59f
--- /dev/null
+++ b/plugins/commands/serve/mappers/capability.rb
@@ -0,0 +1,22 @@
+module VagrantPlugins
+  module CommandServe
+    class Mappers
+      # Extracts a string capability name from a Funcspec value
+      class NamedCapability < Mapper
+        def initialize
+          inputs = [].tap do |i|
+            i << Input.new(type: SDK::FuncSpec::Value) { |arg|
+              arg.type == "hashicorp.vagrant.sdk.Args.NamedCapability" &&
+                !arg&.value&.value.nil?
+            }
+          end
+          super(inputs: inputs, output: String, func: method(:converter))
+        end
+
+        def converter(proto)
+          SDK::Args::NamedCapability.decode(proto.value.value).Capability
+        end
+      end
+    end
+  end
+end
diff --git a/plugins/commands/serve/service/guest_service.rb b/plugins/commands/serve/service/guest_service.rb
index 149af76d6..19ca409bf 100644
--- a/plugins/commands/serve/service/guest_service.rb
+++ b/plugins/commands/serve/service/guest_service.rb
@@ -100,9 +100,8 @@ module VagrantPlugins
 
         def has_capability(req, ctx)
           ServiceInfo.with_info(ctx) do |info|
-            cap_name = req.args.detect { |a|
-              a.type == "hashicorp.vagrant.sdk.Args.NamedCapability"
-            }&.value&.value.strip.gsub("\b", "").gsub("\x05", "")
+            cap_name = mapper.funcspec_map(req).to_sym
+
             plugin_name = info.plugin_name
             LOGGER.debug("checking for #{cap_name} capability in #{plugin_name}")