diff --git a/Makefile b/Makefile
index 5da3cb0..c011301 100644
--- a/Makefile
+++ b/Makefile
@@ -85,6 +85,7 @@ C_SOURCES := \
     clks/kernel/tty.c \
     clks/kernel/pmm.c \
     clks/kernel/heap.c \
+    clks/kernel/keyboard.c \
     clks/kernel/interrupts.c \
     clks/kernel/scheduler.c \
     clks/kernel/elf64.c \
diff --git a/clks/include/clks/keyboard.h b/clks/include/clks/keyboard.h
new file mode 100644
index 0000000..8bba403
--- /dev/null
+++ b/clks/include/clks/keyboard.h
@@ -0,0 +1,10 @@
+#ifndef CLKS_KEYBOARD_H
+#define CLKS_KEYBOARD_H
+
+#include <clks/types.h>
+
+void clks_keyboard_init(void);
+void clks_keyboard_handle_scancode(u8 scancode);
+u64 clks_keyboard_hotkey_switch_count(void);
+
+#endif
diff --git a/clks/kernel/interrupts.c b/clks/kernel/interrupts.c
index de9b758..a9cbf14 100644
--- a/clks/kernel/interrupts.c
+++ b/clks/kernel/interrupts.c
@@ -2,6 +2,7 @@
 #include <clks/cpu.h>
 #include <clks/interrupts.h>
 #include <clks/log.h>
+#include <clks/keyboard.h>
 #include <clks/scheduler.h>
 #include <clks/syscall.h>
 #include <clks/types.h>
@@ -18,9 +19,13 @@
 
 #define CLKS_IRQ_BASE   32U
 #define CLKS_IRQ_TIMER  32U
+#define CLKS_IRQ_KEYBOARD 33U
 #define CLKS_IRQ_LAST   47U
 #define CLKS_SYSCALL_VECTOR 128U
 
+#define CLKS_PS2_DATA_PORT  0x60U
+#define CLKS_PS2_STATUS_PORT 0x64U
+
 struct clks_idt_entry {
     u16 offset_low;
     u16 selector;
@@ -192,7 +197,7 @@ static void clks_pic_remap_and_mask(void) {
     (void)master_mask;
     (void)slave_mask;
 
-    clks_outb(CLKS_PIC1_DATA, 0xFEU);
+    clks_outb(CLKS_PIC1_DATA, 0xFCU);
     clks_outb(CLKS_PIC2_DATA, 0xFFU);
 }
 
@@ -225,6 +230,10 @@ static void clks_load_idt(void) {
     __asm__ volatile("lidt %0" : : "m"(idtr));
 }
 
+
+static clks_bool clks_ps2_has_output(void) {
+    return (clks_inb(CLKS_PS2_STATUS_PORT) & 0x01U) != 0U ? CLKS_TRUE : CLKS_FALSE;
+}
 static void clks_enable_interrupts(void) {
     __asm__ volatile("sti");
 }
@@ -248,6 +257,11 @@ void clks_interrupt_dispatch(struct clks_interrupt_frame *frame) {
     if (vector == CLKS_IRQ_TIMER) {
         clks_timer_ticks++;
         clks_scheduler_on_timer_tick(clks_timer_ticks);
+    } else if (vector == CLKS_IRQ_KEYBOARD) {
+        if (clks_ps2_has_output() == CLKS_TRUE) {
+            u8 scancode = clks_inb(CLKS_PS2_DATA_PORT);
+            clks_keyboard_handle_scancode(scancode);
+        }
     }
 
     if (vector >= CLKS_IRQ_BASE && vector <= CLKS_IRQ_LAST) {
@@ -323,4 +337,4 @@ void clks_interrupts_init(void) {
 
 u64 clks_interrupts_timer_ticks(void) {
     return clks_timer_ticks;
-}
\ No newline at end of file
+}
diff --git a/clks/kernel/keyboard.c b/clks/kernel/keyboard.c
new file mode 100644
index 0000000..0f2ca09
--- /dev/null
+++ b/clks/kernel/keyboard.c
@@ -0,0 +1,53 @@
+#include <clks/keyboard.h>
+#include <clks/log.h>
+#include <clks/tty.h>
+#include <clks/types.h>
+
+#define CLKS_SC_ALT        0x38U
+#define CLKS_SC_F1         0x3BU
+#define CLKS_SC_F2         0x3CU
+#define CLKS_SC_F3         0x3DU
+#define CLKS_SC_F4         0x3EU
+
+static clks_bool clks_kbd_alt_down = CLKS_FALSE;
+static u64 clks_kbd_hotkey_switches = 0ULL;
+
+void clks_keyboard_init(void) {
+    clks_kbd_alt_down = CLKS_FALSE;
+    clks_kbd_hotkey_switches = 0ULL;
+    clks_log(CLKS_LOG_INFO, "KBD", "ALT+F1..F4 TTY HOTKEY ONLINE");
+}
+
+void clks_keyboard_handle_scancode(u8 scancode) {
+    clks_bool released = ((scancode & 0x80U) != 0U) ? CLKS_TRUE : CLKS_FALSE;
+    u8 code = (u8)(scancode & 0x7FU);
+
+    if (code == CLKS_SC_ALT) {
+        clks_kbd_alt_down = (released == CLKS_FALSE) ? CLKS_TRUE : CLKS_FALSE;
+        return;
+    }
+
+    if (released == CLKS_TRUE || clks_kbd_alt_down == CLKS_FALSE) {
+        return;
+    }
+
+    if (code >= CLKS_SC_F1 && code <= CLKS_SC_F4) {
+        u32 target = (u32)(code - CLKS_SC_F1);
+        u32 before = clks_tty_active();
+        u32 after;
+
+        clks_tty_switch(target);
+        after = clks_tty_active();
+
+        if (after != before) {
+            clks_kbd_hotkey_switches++;
+            clks_log(CLKS_LOG_INFO, "TTY", "HOTKEY SWITCH");
+            clks_log_hex(CLKS_LOG_INFO, "TTY", "ACTIVE", (u64)after);
+            clks_log_hex(CLKS_LOG_INFO, "TTY", "HOTKEY_SWITCHES", clks_kbd_hotkey_switches);
+        }
+    }
+}
+
+u64 clks_keyboard_hotkey_switch_count(void) {
+    return clks_kbd_hotkey_switches;
+}
diff --git a/clks/kernel/kmain.c b/clks/kernel/kmain.c
index f226887..20879da 100644
--- a/clks/kernel/kmain.c
+++ b/clks/kernel/kmain.c
@@ -7,6 +7,7 @@
 #include <clks/fs.h>
 #include <clks/heap.h>
 #include <clks/interrupts.h>
+#include <clks/keyboard.h>
 #include <clks/kelf.h>
 #include <clks/kernel.h>
 #include <clks/log.h>
@@ -63,7 +64,7 @@ static void clks_task_usrd(u64 tick) {
     clks_userland_tick(tick);
 }
 
-static void clks_stage14_syscall_probe(void) {
+static void clks_stage15_syscall_probe(void) {
     char child_name[96];
     char read_buf[160];
     u64 root_children;
@@ -170,7 +171,7 @@ void clks_kernel_main(void) {
         clks_tty_init();
     }
 
-    clks_log(CLKS_LOG_INFO, "BOOT", "CLEONOS STAGE14 START");
+    clks_log(CLKS_LOG_INFO, "BOOT", "CLEONOS STAGE15 START");
 
     if (boot_fb == CLKS_NULL) {
         clks_log(CLKS_LOG_WARN, "VIDEO", "NO FRAMEBUFFER FROM LIMINE");
@@ -233,6 +234,7 @@ void clks_kernel_main(void) {
     }
 
     clks_exec_init();
+    clks_keyboard_init();
 
     if (clks_userland_init() == CLKS_FALSE) {
         clks_log(CLKS_LOG_ERROR, "USER", "USERLAND INIT FAILED");
@@ -279,11 +281,10 @@ void clks_kernel_main(void) {
     syscall_ticks = clks_syscall_invoke_kernel(CLKS_SYSCALL_TIMER_TICKS, 0ULL, 0ULL, 0ULL);
     clks_log_hex(CLKS_LOG_INFO, "SYSCALL", "TICKS", syscall_ticks);
 
-    clks_stage14_syscall_probe();
+    clks_stage15_syscall_probe();
 
     clks_log(CLKS_LOG_INFO, "TTY", "VIRTUAL TTY0 READY");
     clks_log(CLKS_LOG_DEBUG, "KERNEL", "IDLE LOOP ENTER");
 
     clks_cpu_halt_forever();
 }
-
diff --git a/docs/stage15.md b/docs/stage15.md
new file mode 100644
index 0000000..18100fd
--- /dev/null
+++ b/docs/stage15.md
@@ -0,0 +1,53 @@
+# CLeonOS Stage15
+
+## Stage Goal
+- Keep ELF path unchanged and continue non-ELF stability work.
+- Add PS/2 keyboard IRQ handling in kernel interrupt path.
+- Support virtual terminal hotkey switching with `Alt+F1`~`Alt+F4`.
+- Keep scheduler, syscall, and existing Stage14 behavior stable.
+
+## What Was Implemented
+- New keyboard module:
+  - `clks/include/clks/keyboard.h`
+  - `clks/kernel/keyboard.c`
+- Interrupt integration:
+  - Enable IRQ1 (keyboard) alongside IRQ0 in PIC mask.
+  - Read scancode from PS/2 data port `0x60`.
+  - Dispatch scancode to keyboard hotkey handler.
+- Hotkey behavior:
+  - Hold `Alt` + press `F1/F2/F3/F4` to switch TTY 0/1/2/3.
+  - On successful switch, kernel logs active TTY and switch counter.
+- Boot stage update:
+  - `CLEONOS STAGE15 START`.
+
+## Acceptance Criteria
+- Kernel boots and prints `CLEONOS STAGE15 START`.
+- Boot logs include keyboard module online message:
+  - `[INFO][KBD] ALT+F1..F4 TTY HOTKEY ONLINE`
+- In QEMU runtime:
+  - Press `Alt+F2` / `Alt+F3` / `Alt+F4` / `Alt+F1`.
+  - Logs show:
+    - `[INFO][TTY] HOTKEY SWITCH`
+    - `[INFO][TTY] ACTIVE: 0X...`
+    - `[INFO][TTY] HOTKEY_SWITCHES: 0X...`
+
+## Build Targets
+- `make setup`
+- `make userapps`
+- `make iso`
+- `make run`
+- `make debug`
+
+## QEMU Command
+- `qemu-system-x86_64 -M q35 -m 1024M -cdrom build/CLeonOS-x86_64.iso -serial stdio`
+
+## Common Bugs and Debugging
+- Hotkey has no effect:
+  - Verify QEMU window is focused and keyboard input is captured.
+  - Confirm logs show Stage15 keyboard online message.
+- IRQ timer works but keyboard does not:
+  - Re-check PIC mask includes IRQ1 (master mask should allow IRQ0 and IRQ1).
+- Wrong function key mapping:
+  - Current mapping is Set1 scancode: F1=0x3B, F2=0x3C, F3=0x3D, F4=0x3E.
+- Excessive hotkey logs:
+  - Holding key may repeat make scancode by keyboard auto-repeat; this is expected in current stage.