diff --git a/apps/twnlua/CMakeLists.txt b/apps/twnlua/CMakeLists.txt
index ff7b902..36af1c6 100644
--- a/apps/twnlua/CMakeLists.txt
+++ b/apps/twnlua/CMakeLists.txt
@@ -19,6 +19,17 @@ add_custom_command(
    CODEGEN
 )
 
+add_custom_command(
+   OUTPUT ${CMAKE_SOURCE_DIR}/data/scripts/twnapi.lua
+   COMMAND ${PYTHON3} ${CMAKE_CURRENT_SOURCE_DIR}/docgen.py $ENV{TWNROOT}/share/twn_api.json > ${CMAKE_SOURCE_DIR}/data/scripts/twnapi.lua
+   DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/docgen.py $ENV{TWNROOT}/share/twn_api.json
+)
+
+add_custom_target(
+    twnlua_docgen ALL
+    DEPENDS ${CMAKE_SOURCE_DIR}/data/scripts/twnapi.lua
+)
+
 add_compile_definitions(LUA_32BITS)
 
 set(SOURCE_FILES