diff --git a/exe/fusuma b/exe/fusuma
index f52391e..9665288 100755
--- a/exe/fusuma
+++ b/exe/fusuma
@@ -27,6 +27,10 @@ opt.on('--log=path/to/file',
   option[:log_filepath] = v
 end
 
+opt.on('--show-config', 'Show config as YAML format which is loaded internally') do |v|
+  option[:show_config] = v
+end
+
 opt.on('--device="Device name"',
        'Open the given device only (DEPRECATED)') do |v|
   option[:device] = v
diff --git a/lib/fusuma.rb b/lib/fusuma.rb
index da3f281..31d5ff9 100644
--- a/lib/fusuma.rb
+++ b/lib/fusuma.rb
@@ -27,13 +27,18 @@ def read_options(option)
         MultiLogger.filepath = option[:log_filepath]
         MultiLogger.instance.debug_mode = option[:verbose]
 
-        load_custom_config(option[:config_path])
-
         Plugin::Manager.require_base_plugins
 
+        load_custom_config(option[:config_path])
+
         Environment.dump_information
         Kernel.exit(0) if option[:version]
 
+        if option[:show_config]
+          Environment.print_config
+          Kernel.exit(0)
+        end
+
         if option[:list]
           Environment.print_device_list
           Kernel.exit(0)
diff --git a/lib/fusuma/config.rb b/lib/fusuma/config.rb
index 5057b7f..8c6bdb0 100644
--- a/lib/fusuma/config.rb
+++ b/lib/fusuma/config.rb
@@ -46,16 +46,46 @@ def custom_path=(new_path)
     end
 
     def reload
+      plugin_defaults = {
+        context: :plugin_defaults,
+        plugin: {}
+      }
+
+      plugin_defaults_paths.each do |default_yml|
+        plugin_defaults.deep_merge!(validate(default_yml)[0])
+      end
+
+      find_config_filepath.tap do |path|
+        MultiLogger.info "reload config: #{path}"
+
+        @keymap = validate(path).tap do |yamls|
+          yamls << plugin_defaults
+        end
+      end
+
+      # reset searcher cache
       @searcher = Searcher.new
-      path = find_filepath
-      MultiLogger.info "reload config: #{path}"
-      @keymap = validate(path)
+
       self
     rescue InvalidFileError => e
       MultiLogger.error e.message
       exit 1
     end
 
+    # @param key [Symbol]
+    # @param base [Config::Index]
+    # @return [Hash]
+    def fetch_config_params(key, base)
+      [{}, :plugin_defaults].find do |context|
+        ret = Config::Searcher.with_context(context) do
+          Config.search(base)
+        end
+        if ret&.key?(key)
+          return ret
+        end
+      end || {}
+    end
+
     # @return [Hash] If check passes
     # @raise [InvalidFileError] If check does not pass
     def validate(path)
@@ -75,7 +105,6 @@ def validate(path)
     end
 
     # @param index [Index]
-    # @param context [Hash]
     def search(index)
       @searcher.search_with_cache(index, location: keymap)
     end
@@ -95,7 +124,7 @@ def find_execute_key(index)
 
     private
 
-    def find_filepath
+    def find_config_filepath
       filename = "fusuma/config.yml"
       if custom_path
         return expand_custom_path if File.exist?(expand_custom_path)
@@ -120,5 +149,12 @@ def expand_config_path(filename)
     def expand_default_path(filename)
       File.expand_path "../../#{filename}", __FILE__
     end
+
+    def plugin_defaults_paths
+      Plugin::Manager.load_paths.map do |plugin_path|
+        yml = plugin_path.gsub(/\.rb$/, ".yml")
+        yml if File.exist?(yml)
+      end.compact
+    end
   end
 end
diff --git a/lib/fusuma/config/searcher.rb b/lib/fusuma/config/searcher.rb
index 5e6da64..1b2fd5f 100644
--- a/lib/fusuma/config/searcher.rb
+++ b/lib/fusuma/config/searcher.rb
@@ -111,7 +111,6 @@ def find_context(request_context, &block)
         end
 
         attr_reader :context
-
       end
     end
   end
diff --git a/lib/fusuma/environment.rb b/lib/fusuma/environment.rb
index 9957e76..94127a1 100644
--- a/lib/fusuma/environment.rb
+++ b/lib/fusuma/environment.rb
@@ -39,6 +39,12 @@ def print_device_list
           puts device.name
         end
       end
+
+      def print_config
+        Config.instance.keymap.each do |conf|
+          puts conf.deep_stringify_keys.to_yaml
+        end
+      end
     end
   end
 end
diff --git a/lib/fusuma/hash_support.rb b/lib/fusuma/hash_support.rb
index 0a7c49f..ae3edca 100644
--- a/lib/fusuma/hash_support.rb
+++ b/lib/fusuma/hash_support.rb
@@ -2,6 +2,28 @@
 
 # Patch to hash
 class Hash
+  # activesupport-5.2.0/lib/active_support/core_ext/hash/deep_merge.rb
+  def deep_merge(other_hash, &block)
+    dup.deep_merge!(other_hash, &block)
+  end
+
+  # Same as +deep_merge+, but modifies +self+.
+  def deep_merge!(other_hash, &block)
+    merge!(other_hash) do |key, this_val, other_val|
+      if this_val.is_a?(Hash) && other_val.is_a?(Hash)
+        this_val.deep_merge(other_val, &block)
+      elsif block
+        block.call(key, this_val, other_val)
+      else
+        other_val
+      end
+    end
+  end
+
+  def deep_stringify_keys
+    deep_transform_keys(&:to_s)
+  end
+
   # activesupport-4.1.1/lib/active_support/core_ext/hash/keys.rb
   def deep_symbolize_keys
     deep_transform_keys do |key|
diff --git a/lib/fusuma/plugin/base.rb b/lib/fusuma/plugin/base.rb
index 1fcb819..b041404 100644
--- a/lib/fusuma/plugin/base.rb
+++ b/lib/fusuma/plugin/base.rb
@@ -31,14 +31,20 @@ def config_param_types
         raise NotImplementedError, "override #{self.class.name}##{__method__}"
       end
 
+      # @param key [Symbol]
+      # @param base [Config::Index]
       # @return [Object]
-      def config_params(key = nil, base: config_index)
-        params = Config.search(base) || {}
+      def config_params(key = nil)
+        @config_params ||= {}
+        if @config_params["#{config_index.cache_key},#{key}"]
+          return @config_params["#{config_index.cache_key},#{key}"]
+        end
+
+        params = Config.instance.fetch_config_params(key, config_index)
 
         return params unless key
 
-        @config_params ||= {}
-        @config_params["#{base.cache_key},#{key}"] ||=
+        @config_params["#{config_index.cache_key},#{key}"] =
           params.fetch(key, nil).tap do |val|
             next if val.nil?
 
@@ -55,7 +61,7 @@ def config_params(key = nil, base: config_index)
       end
 
       def config_index
-        Config::Index.new(self.class.name.gsub("Fusuma::", "").underscore.split("/"))
+        @config_index ||= Config::Index.new(self.class.name.gsub("Fusuma::", "").underscore.split("/"))
       end
     end
   end
diff --git a/lib/fusuma/plugin/inputs/libinput_command_input.yml b/lib/fusuma/plugin/inputs/libinput_command_input.yml
new file mode 100644
index 0000000..87da0fa
--- /dev/null
+++ b/lib/fusuma/plugin/inputs/libinput_command_input.yml
@@ -0,0 +1,3 @@
+plugin:
+  inputs:
+    libinput_command_input:
diff --git a/lib/fusuma/plugin/manager.rb b/lib/fusuma/plugin/manager.rb
index d6388a3..6f8d505 100644
--- a/lib/fusuma/plugin/manager.rb
+++ b/lib/fusuma/plugin/manager.rb
@@ -115,6 +115,12 @@ def plugins
           @plugins ||= {}
         end
 
+        # @return [Array<String>]
+        # @example
+        #   Manager.load_paths
+        #   => ["/path/to/fusuma/lib/fusuma/plugin/inputs/input.rb",
+        #       "/path/to/fusuma/lib/fusuma/plugin/inputs/libinput_command_input.rb",
+        #       "/path/to/fusuma/lib/fusuma/plugin/inputs/timer_input.rb"]
         def load_paths
           @load_paths ||= []
         end
diff --git a/spec/fusuma/config/searcher_spec.rb b/spec/fusuma/config/searcher_spec.rb
index 741e355..20f3aff 100644
--- a/spec/fusuma/config/searcher_spec.rb
+++ b/spec/fusuma/config/searcher_spec.rb
@@ -57,7 +57,7 @@ module Fusuma
             ]
           end
           it "detects ctrl+minus with skip" do
-            value =  Config::Searcher.new.search(index, location: location)
+            value = Config::Searcher.new.search(index, location: location)
             expect(value).to eq("ctrl+minus")
           end
         end
diff --git a/spec/fusuma/plugin/buffers/buffer_spec.rb b/spec/fusuma/plugin/buffers/buffer_spec.rb
index 1d16868..1656759 100644
--- a/spec/fusuma/plugin/buffers/buffer_spec.rb
+++ b/spec/fusuma/plugin/buffers/buffer_spec.rb
@@ -71,8 +71,8 @@ module Buffers
             Config.custom_path = nil
           end
 
-          subject { @buffer.config_params }
-          it { is_expected.to eq(dummy: "dummy") }
+          subject { @buffer.config_params(:dummy) }
+          it { is_expected.to eq("dummy") }
         end
       end
     end
diff --git a/spec/fusuma/plugin/buffers/gesture_buffer_spec.rb b/spec/fusuma/plugin/buffers/gesture_buffer_spec.rb
index c59af52..8176076 100644
--- a/spec/fusuma/plugin/buffers/gesture_buffer_spec.rb
+++ b/spec/fusuma/plugin/buffers/gesture_buffer_spec.rb
@@ -102,7 +102,7 @@ module Buffers
             end
 
             it "should keep only events generated within 0.3 seconds" do
-              expect(@buffer.config_params).to eq(seconds_to_keep: 0.3)
+              expect(@buffer.config_params(:seconds_to_keep)).to eq(0.3)
               time = Time.now
               event1 = @event_generator.call(time)
               @buffer.buffer(event1)
diff --git a/spec/fusuma/plugin/detectors/detector_spec.rb b/spec/fusuma/plugin/detectors/detector_spec.rb
index a81d160..d35cc8d 100644
--- a/spec/fusuma/plugin/detectors/detector_spec.rb
+++ b/spec/fusuma/plugin/detectors/detector_spec.rb
@@ -35,7 +35,7 @@ module Detectors
         end
 
         describe "#config_params" do
-          it { expect(@detector.config_params).to eq(dummy: "dummy") }
+          it { expect(@detector.config_params(:dummy)).to eq("dummy") }
         end
       end
     end
diff --git a/spec/fusuma/plugin/detectors/dummy_detector.rb b/spec/fusuma/plugin/detectors/dummy_detector.rb
index 87b675e..81ed638 100644
--- a/spec/fusuma/plugin/detectors/dummy_detector.rb
+++ b/spec/fusuma/plugin/detectors/dummy_detector.rb
@@ -18,6 +18,12 @@ def detect(buffers)
             return create_event(record: record)
           end
         end
+
+        def config_param_types
+          {
+            dummy: String
+          }
+        end
       end
     end
   end
diff --git a/spec/fusuma/plugin/executors/executor_spec.rb b/spec/fusuma/plugin/executors/executor_spec.rb
index 94e2298..8373182 100644
--- a/spec/fusuma/plugin/executors/executor_spec.rb
+++ b/spec/fusuma/plugin/executors/executor_spec.rb
@@ -27,6 +27,12 @@ module Executors
       end
 
       class DummyExecutor < Executor
+        def config_param_types
+          {
+            dummy: String
+          }
+        end
+
         def execute_keys
           [:dummy]
         end
@@ -171,7 +177,7 @@ def executable?(event)
         end
 
         describe "#config_params" do
-          it { expect(@executor.config_params).to eq(dummy: "dummy") }
+          it { expect(@executor.config_params(:dummy)).to eq("dummy") }
         end
       end
     end
diff --git a/spec/fusuma/plugin/filters/filter_spec.rb b/spec/fusuma/plugin/filters/filter_spec.rb
index d645c50..eb8431f 100644
--- a/spec/fusuma/plugin/filters/filter_spec.rb
+++ b/spec/fusuma/plugin/filters/filter_spec.rb
@@ -15,7 +15,8 @@ class DummyFilter < Filter
 
         def config_param_types
           {
-            source: String
+            source: String,
+            dummy: String,
           }
         end
       end
@@ -83,8 +84,8 @@ def config_param_types
             Config.custom_path = nil
           end
 
-          subject { filter.config_params }
-          it { is_expected.to eq(dummy: "dummy") }
+          subject { filter.config_params(:dummy) }
+          it { is_expected.to eq("dummy") }
         end
       end
     end
diff --git a/spec/fusuma/plugin/inputs/input_spec.rb b/spec/fusuma/plugin/inputs/input_spec.rb
index b569c1c..1ae758a 100644
--- a/spec/fusuma/plugin/inputs/input_spec.rb
+++ b/spec/fusuma/plugin/inputs/input_spec.rb
@@ -29,6 +29,12 @@ module Inputs
       end
 
       class DummyInput < Input
+        def config_param_types
+          {
+            dummy: String
+          }
+        end
+
         def io
           @io ||= begin
             r, w = IO.pipe
@@ -61,8 +67,8 @@ def io
         end
 
         describe "#config_params" do
-          subject { dummy_input.config_params }
-          it { is_expected.to eq(dummy: "dummy") }
+          subject { dummy_input.config_params(:dummy) }
+          it { is_expected.to eq("dummy") }
         end
       end
     end