diff --git a/plugins/commands/serve/service/host_service.rb b/plugins/commands/serve/service/host_service.rb
index a2d90db16..40b7d39fc 100644
--- a/plugins/commands/serve/service/host_service.rb
+++ b/plugins/commands/serve/service/host_service.rb
@@ -1,3 +1,5 @@
+require "google/protobuf/well_known_types"
+
 module VagrantPlugins
   module CommandServe
     module Service
@@ -5,20 +7,137 @@ module VagrantPlugins
         prepend Util::HasBroker
         prepend Util::ExceptionLogger
 
-        def detect_spec(*args)
-          Hashicorp::Vagrant::Sdk::FuncSpec.new
+        def detect_spec(*_)
+          SDK::FuncSpec.new(
+            name: "detect_spec",
+            result: [
+              type: "hashicorp.vagrant.sdk.Host.DetectResp",
+              name: "",
+            ]
+          )
         end
 
-        def detect(*args)
-          plugin_name = args.last.metadata["plugin_name"]
-          plugin = Vagrant::Plugin::V2::Plugin.manager.hosts[plugin_name.to_sym].to_a.first
-          if !plugin
-            raise "Failed to locate host plugin for: #{plugin_name}"
+        def detect(req, ctx)
+          ServiceInfo.with_info(ctx) do |info|
+            plugin_name = info.plugin_name
+            plugin = Vagrant.plugin("2").manager.hosts[plugin_name.to_s.to_sym].to_a.first
+            if !plugin
+              raise "Failed to locate host plugin for: #{plugin_name.inspect}"
+            end
+            host = plugin.new
+            SDK::Host::DetectResp.new(
+              detected: host.detect?({}), # TODO(spox): argument should be env/state bag
+            )
           end
-          Hashicorp::Vagrant::Sdk::Host::DetectResp.new(
-            detected: plugin.new.detect?({})
+        end
+
+        def parents_spec(*_)
+          SDK::FuncSpec.new(
+            name: "parents_spec",
+            result: [
+              type: "hashicorp.vagrant.sdk.Host.ParentsResp",
+              name: "",
+            ]
           )
         end
+
+        def parents(req, ctx)
+          ServiceInfo.with_info(ctx) do |info|
+            plugin_name = info.plugin_name
+            plugin = Vagrant.plugin("2").manager.hosts[plugin_name.to_s.to_sym].to_a.first
+            if !plugin
+              raise "Failed to locate host plugin for: #{plugin_name.inspect}"
+            end
+            SDK::Host::ParentsResp.new(
+              parents: plugin.new.parents
+            )
+          end
+        end
+
+        def has_capability_spec(*_)
+          SDK::FuncSpec.new(
+            name: "has_capability_spec",
+            args: [
+              SDK::FuncSpec::Value.new(
+                type: "hashicorp.vagrant.sdk.Args.NamedCapability",
+                name: "",
+              )
+            ],
+            result: [
+              SDK::FuncSpec::Value.new(
+                type: "hashicorp.vagrant.sdk.Host.Capability.CheckResp",
+                name: "",
+              ),
+            ],
+          )
+        end
+
+        def has_capability(req, ctx)
+          ServiceInfo.with_info(ctx) do |info|
+            plugin_name = info.plugin_name
+            n_cap = req.args.detect { |a|
+              a.type == 'hashicorp.vagrant.sdk.Args.NamedCapability'
+            }&.value&.value
+            p = Vagrant::Host.new(
+              plugin_name.to_sym,
+              Vagrant.plugin("2").manager.hosts,
+              Vagrant.plugin("2").manager.host_capabilities,
+              nil,
+            )
+            SDK::Host::Capability::CheckResp.new(
+              has_capability: p.capability?(n_cap.strip.to_s.to_sym)
+            )
+          end
+        end
+
+        def capability_spec(*_)
+          SDK::FuncSpec.new(
+            name: "capability_spec",
+            args: [
+              SDK::FuncSpec::Value.new(
+                type: "hashicorp.vagrant.sdk.Args.TerminalUI",
+                name: "",
+              ),
+            ],
+            result: [
+              SDK::FuncSpec::Value.new(
+                type: "hashicorp.vagrant.sdk.Host.Capability.Resp"
+              )
+            ]
+          )
+        end
+
+        def capability(req, ctx)
+          ServiceInfo.with_info(ctx) do |info|
+            begin
+
+              res = nil
+              plugin_name = info.plugin_name
+              n_cap = req.name
+              raw_terminal = req.func_args.args.detect { |a|
+                a.type == "hashicorp.vagrant.sdk.Args.TerminalUI"
+              }&.value&.value
+              ui_client = Client::Terminal.load(raw_terminal, broker: broker)
+              ui = Vagrant::UI::RemoteUI.new(ui_client)
+
+              p = Vagrant::Host.new(
+                plugin_name.to_sym,
+                Vagrant.plugin("2").manager.hosts,
+                Vagrant.plugin("2").manager.host_capabilities,
+                nil,
+              )
+              res = p.capability(n_cap.to_s.strip.to_sym, ui) # TODO(spox): first arg needs to be env / statebag
+              vres = Google::Protobuf::Value.new
+              vres.from_ruby(res)
+
+              SDK::Host::Capability::Resp.new(
+                result: Google::Protobuf::Any.pack(vres)
+              )
+            rescue => err
+              raise "#{err.class}: #{err}\n#{err.backtrace.join("\n")}"
+            end
+          end
+        end
       end
     end
   end