diff --git a/type_description_interfaces/CMakeLists.txt b/type_description_interfaces/CMakeLists.txt
index e860c778..c3ac72bf 100644
--- a/type_description_interfaces/CMakeLists.txt
+++ b/type_description_interfaces/CMakeLists.txt
@@ -2,9 +2,9 @@ cmake_minimum_required(VERSION 3.5)
 
 project(type_description_interfaces)
 
-# Default to C++14
+# Default to C++17
 if(NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 14)
+  set(CMAKE_CXX_STANDARD 17)
 endif()
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(-Wall -Wextra -Wpedantic)
@@ -19,7 +19,10 @@ rosidl_generate_interfaces(${PROJECT_NAME}
   "msg/Field.msg"
   "msg/FieldType.msg"
   "msg/IndividualTypeDescription.msg"
+  "msg/KeyValue.msg"
   "msg/TypeDescription.msg"
+  "msg/TypeSource.msg"
+  "srv/GetTypeDescription.srv"
   ADD_LINTER_TESTS
 )
 
diff --git a/type_description_interfaces/msg/KeyValue.msg b/type_description_interfaces/msg/KeyValue.msg
new file mode 100644
index 00000000..b06a1617
--- /dev/null
+++ b/type_description_interfaces/msg/KeyValue.msg
@@ -0,0 +1,4 @@
+# Represents an arbitrary key-value pair for application-specific information.
+
+string key
+string value
diff --git a/type_description_interfaces/msg/TypeSource.msg b/type_description_interfaces/msg/TypeSource.msg
new file mode 100644
index 00000000..7c945270
--- /dev/null
+++ b/type_description_interfaces/msg/TypeSource.msg
@@ -0,0 +1,16 @@
+# Represents the original source of a ROS 2 interface definition.
+
+# ROS interface type name, in PACKAGE/NAMESPACE/TYPENAME format.
+string type_name
+
+# The type of the original source file, typically matching the file extension.
+# Well-known encodings: "idl", "msg", "srv", "action", "dynamic", "implicit".
+# "dynamic" specifies a type created programmatically by a user, thus having no source.
+# "implicit" specifies a type created automatically as a subtype of a
+# complex type (service or action) - such as the request message for a service.
+# Implicit types will have no contents, the full source will be available on the parent srv/action.
+string encoding
+
+# Dumped contents of the interface definition source file.
+# If `encoding` is "dynamic" or "implicit", this field will be empty.
+string raw_file_contents
diff --git a/type_description_interfaces/package.xml b/type_description_interfaces/package.xml
index dd3fe970..f3fd1e14 100644
--- a/type_description_interfaces/package.xml
+++ b/type_description_interfaces/package.xml
@@ -13,6 +13,8 @@
 
   <buildtool_depend>rosidl_core_generators</buildtool_depend>
 
+  <depend>service_msgs</depend>
+
   <exec_depend>rosidl_core_runtime</exec_depend>
 
   <test_depend>ament_lint_auto</test_depend>
diff --git a/type_description_interfaces/srv/GetTypeDescription.srv b/type_description_interfaces/srv/GetTypeDescription.srv
new file mode 100644
index 00000000..9d34d0d0
--- /dev/null
+++ b/type_description_interfaces/srv/GetTypeDescription.srv
@@ -0,0 +1,29 @@
+# ROS interface type name, in PACKAGE/NAMESPACE/TYPENAME format.
+string type_name
+
+# REP-2011 RIHS hash string.
+string type_hash
+
+# Whether to return the original idl/msg/etc. source file(s) in the response.
+bool include_type_sources true
+---
+# True if the type description information is available and populated in the response.
+# If false, all other fields except `failure_reason` are considered undefined.
+bool successful
+# If `successful` is false, contains a reason for failure.
+# If `successful` is true, this is left empty.
+string failure_reason
+
+# The parsed type description which can be used programmatically.
+TypeDescription type_description
+
+# A list containing the interface definition source text of the requested type,
+# plus all types it recursively depends on.
+# Each source text is a copy of the original contents of the
+# .msg, .srv, .action, .idl, or other file if it exists, including comments and whitespace.
+# Sources can be matched with IndividualTypeDescriptions by their `type_name`.
+# The `encoding` field of each entry informs how to interpret its contents.
+TypeSource[] type_sources
+
+# Key-value pairs of extra information.
+KeyValue[] extra_information