diff --git a/CMakeLists.txt b/CMakeLists.txt
index 890f9db..ae8ac65 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,6 +12,12 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/bin)
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/bin)
 
+file(
+    COPY ${PROJECT_SOURCE_DIR}/src/klotski_core/klotski.h
+    DESTINATION ${PROJECT_SOURCE_DIR}/bin
+    FOLLOW_SYMLINK_CHAIN
+)
+
 # TODO: only in libklotski.so
 add_compile_options(-fPIC)
 
diff --git a/src/demo.py b/src/demo.py
index bb877df..4fd69c8 100755
--- a/src/demo.py
+++ b/src/demo.py
@@ -2,6 +2,6 @@
 
 import ctypes
 
-lib = ctypes.CDLL('../cmake-build-release/src/klotski_core/libklotski.so')
+lib = ctypes.CDLL('../bin/libklotski.so')
 
 lib.tmain()
diff --git a/src/klotski_core/klotski.h b/src/klotski_core/klotski.h
index 72bec22..9d72867 100644
--- a/src/klotski_core/klotski.h
+++ b/src/klotski_core/klotski.h
@@ -22,7 +22,7 @@ extern "C" {
 #ifdef __cplusplus
 extern "C" {
 #endif
-    /// version -> major.minor.patch
+    // version -> major.minor.patch
     extern int get_version_major();
     extern int get_version_minor();
     extern int get_version_patch();
@@ -62,7 +62,7 @@ extern "C" {
 #ifdef __cplusplus
 extern "C" {
 #endif
-    /// short code warm up api
+    // short code index warm up
     extern void short_code_enable();
     extern void short_code_enable_fast();
     extern bool is_short_code_available();
@@ -72,6 +72,7 @@ extern "C" {
     extern bool short_code_check(uint32_t short_code);
     extern bool common_code_check(uint64_t common_code);
 
+    // TODO: allow unsafe convert
     extern bool raw_code_to_short_code(uint64_t raw_code, uint32_t *short_code);
     extern bool short_code_to_raw_code(uint32_t short_code, uint64_t *raw_code);
     extern bool raw_code_to_common_code(uint64_t raw_code, uint64_t *common_code);
@@ -79,12 +80,10 @@ extern "C" {
     extern bool short_code_to_common_code(uint32_t short_code, uint64_t *common_code);
     extern bool common_code_to_short_code(uint64_t common_code, uint32_t *short_code);
 
-    /// output char[] buffer at least 6-bytes
     extern const uint32_t SHORT_CODE_STR_SIZE;
     extern bool short_code_to_string(uint32_t short_code, char short_code_str[]);
     extern bool short_code_from_string(const char short_code_str[], uint32_t *short_code);
 
-    /// output char[] buffer at least 10-bytes
     extern const uint32_t COMMON_CODE_STR_SIZE;
     extern bool common_code_to_string(uint64_t common_code, char common_code_str[]);
     extern bool common_code_to_string_shorten(uint64_t common_code, char common_code_str[]);
diff --git a/src/rust_ffi/wrapper.h b/src/rust_ffi/wrapper.h
index 5b97c58..2fcfc5e 100644
--- a/src/rust_ffi/wrapper.h
+++ b/src/rust_ffi/wrapper.h
@@ -1,3 +1,3 @@
 #pragma once
 
-#include "../klotski_core/klotski.h"
+#include "../../bin/klotski.h"