diff --git a/cimery/crates/viewer/build.rs b/cimery/crates/viewer/build.rs
new file mode 100644
index 0000000..80e5850
--- /dev/null
+++ b/cimery/crates/viewer/build.rs
@@ -0,0 +1,45 @@
+//! 빌드 타임스탬프를 환경변수 BUILD_TIMESTAMP 로 내보냄.
+//! `env!("BUILD_TIMESTAMP")` 로 소비. 사용자가 실행 중인 바이너리가 최신 빌드인지
+//! 타이틀 바에서 즉시 확인할 수 있게 함.
+
+use std::process::Command;
+
+fn main() {
+    // 항상 재실행 → 타임스탬프가 매 빌드마다 갱신.
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=src");
+
+    let ts = current_timestamp();
+    println!("cargo:rustc-env=BUILD_TIMESTAMP={}", ts);
+}
+
+fn current_timestamp() -> String {
+    // Windows: PowerShell / Unix: date. 실패 시 epoch 초.
+    #[cfg(target_os = "windows")]
+    let out = Command::new("powershell")
+        .args([
+            "-NoProfile",
+            "-Command",
+            "Get-Date -Format 'yyyy-MM-dd HH:mm:ss'",
+        ])
+        .output();
+
+    #[cfg(not(target_os = "windows"))]
+    let out = Command::new("date").args(["+%Y-%m-%d %H:%M:%S"]).output();
+
+    if let Ok(o) = out {
+        if o.status.success() {
+            let s = String::from_utf8_lossy(&o.stdout).trim().to_string();
+            if !s.is_empty() {
+                return s;
+            }
+        }
+    }
+    // 폴백: Unix epoch 초
+    use std::time::{SystemTime, UNIX_EPOCH};
+    let secs = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or(0);
+    format!("epoch-{secs}")
+}
diff --git a/cimery/crates/viewer/src/lib.rs b/cimery/crates/viewer/src/lib.rs
index c833f74..37aa6d3 100644
--- a/cimery/crates/viewer/src/lib.rs
+++ b/cimery/crates/viewer/src/lib.rs
@@ -882,14 +882,16 @@ impl Default for CimeryApp {
     fn default() -> Self { Self::new() }
 }
 
+/// 빌드 타임스탬프 (build.rs 에서 주입). 타이틀에 표시해서 사용자가 실행 중인
+/// 바이너리가 최신 빌드인지 즉시 확인 가능.
+const BUILD_TS: &str = env!("BUILD_TIMESTAMP");
+
 impl ApplicationHandler for CimeryApp {
     fn resumed(&mut self, event_loop: &ActiveEventLoop) {
+        let kernel = if cfg!(feature = "occt") { "OcctKernel" } else { "PureRustKernel" };
+        let title = format!("cimery viewer [{kernel}] — build {BUILD_TS}");
         let attrs = Window::default_attributes()
-            .with_title(if cfg!(feature = "occt") {
-                "cimery viewer [Sprint 4 — Full Bridge / OcctKernel]"
-            } else {
-                "cimery viewer [Sprint 4 — Full Bridge / PureRustKernel]"
-            })
+            .with_title(title)
             .with_inner_size(winit::dpi::LogicalSize::new(1280u32, 720u32));
         let window = Arc::new(
             event_loop.create_window(attrs).expect("create window"),