diff --git a/Cargo.lock b/Cargo.lock
index 2fcadaf..31f6f17 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -658,8 +658,8 @@ dependencies = [
  "crossterm",
  "mruby-compiler2-sys",
  "mrubyedge 1.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "mrubyedge-math 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "mrubyedge-time 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mrubyedge-math 0.1.1",
+ "mrubyedge-time 0.1.2",
  "nom",
  "rand",
  "syn",
@@ -668,23 +668,23 @@ dependencies = [
 [[package]]
 name = "mrubyedge-math"
 version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94ab341d1a13e87a66cde9725f0a2f15a2e88c806b7995d9eb69968f4162fa45"
 dependencies = [
- "mec-mrbc-sys",
  "mrubyedge 1.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "mrubyedge-math"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94ab341d1a13e87a66cde9725f0a2f15a2e88c806b7995d9eb69968f4162fa45"
+version = "0.1.2"
 dependencies = [
+ "mec-mrbc-sys",
  "mrubyedge 1.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "mrubyedge-serde-json"
-version = "0.1.1"
+version = "0.1.2"
 dependencies = [
  "mec-mrbc-sys",
  "mrubyedge 1.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -695,19 +695,19 @@ dependencies = [
 [[package]]
 name = "mrubyedge-time"
 version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "143c9c3b434a5c16e206d2cb18917f8b6a8e035259b01029a2c7f9196a9642ec"
 dependencies = [
  "libc",
- "mec-mrbc-sys",
  "mrubyedge 1.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "mrubyedge-time"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "143c9c3b434a5c16e206d2cb18917f8b6a8e035259b01029a2c7f9196a9642ec"
+version = "0.1.3"
 dependencies = [
  "libc",
+ "mec-mrbc-sys",
  "mrubyedge 1.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
diff --git a/mruby-math/Cargo.toml b/mruby-math/Cargo.toml
index f00378d..606e924 100644
--- a/mruby-math/Cargo.toml
+++ b/mruby-math/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "mrubyedge-math"
-version = "0.1.1"
+version = "0.1.2"
 edition = "2024"
 authors = ["Uchio Kondo <udzura@udzura.jp>"]
 description = "mruby-math provides Math module for mruby/edge"
diff --git a/mruby-math/src/lib.rs b/mruby-math/src/lib.rs
index 4a7d790..431a5da 100644
--- a/mruby-math/src/lib.rs
+++ b/mruby-math/src/lib.rs
@@ -10,6 +10,10 @@ use mrubyedge::{
 };
 
 pub fn init_math(vm: &mut VM) {
+    if vm.get_const_by_name("Math").is_some() {
+        return;
+    }
+
     let math_module = vm.define_module("Math", None);
 
     // Define constants
diff --git a/mruby-serde-json/Cargo.toml b/mruby-serde-json/Cargo.toml
index 4c87cef..3fee489 100644
--- a/mruby-serde-json/Cargo.toml
+++ b/mruby-serde-json/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "mrubyedge-serde-json"
-version = "0.1.1"
+version = "0.1.2"
 edition = "2024"
 authors = ["Uchio Kondo <udzura@udzura.jp>"]
 description = "mruby-serde-json provides JSON serialization/deserialization for mruby/edge using serde_json"
diff --git a/mruby-serde-json/src/lib.rs b/mruby-serde-json/src/lib.rs
index c8cb96d..448c713 100644
--- a/mruby-serde-json/src/lib.rs
+++ b/mruby-serde-json/src/lib.rs
@@ -8,6 +8,10 @@ use mrubyedge::{
 };
 
 pub fn init_json(vm: &mut VM) {
+    if vm.get_const_by_name("JSON").is_some() {
+        return;
+    }
+
     let json_class = vm.define_class("JSON", None, None);
 
     mrb_define_class_cmethod(
diff --git a/mruby-time/Cargo.toml b/mruby-time/Cargo.toml
index 4e6956e..e054210 100644
--- a/mruby-time/Cargo.toml
+++ b/mruby-time/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "mrubyedge-time"
-version = "0.1.2"
+version = "0.1.3"
 edition = "2024"
 authors = ["Uchio Kondo <udzura@udzura.jp>"]
 description = "mruby-time provides Time class for mruby/edge"
diff --git a/mruby-time/src/lib.rs b/mruby-time/src/lib.rs
index 1977a26..0e0cf2d 100644
--- a/mruby-time/src/lib.rs
+++ b/mruby-time/src/lib.rs
@@ -475,6 +475,10 @@ fn float_to_sec_nsec(obj: &RObject) -> Result<(i64, u32), Error> {
 /// Initialize the Time class in the VM.
 /// Call this after `VM::open` to make `Time` available in Ruby code.
 pub fn init_time(vm: &mut VM) {
+    if vm.get_const_by_name("Time").is_some() {
+        return;
+    }
+
     let time_class = vm.define_class("Time", None, None);
 
     // Class methods