diff --git a/kitty/client.py b/kitty/client.py
index ab727b681..3417f4ad5 100644
--- a/kitty/client.py
+++ b/kitty/client.py
@@ -12,8 +12,8 @@ from contextlib import suppress
 from typing import Any
 
 
-CSI = '\033['
-OSC = '\033]'
+CSI = '\x1b['
+OSC = '\x1b]'
 
 
 def write(x: str) -> None:
@@ -42,11 +42,11 @@ def screen_alternate_keypad_mode() -> None:
 
 
 def screen_cursor_position(y: int, x: int) -> None:
-    write(CSI + f'{y};{x}H')
+    write(f'{CSI}{y};{x}H')
 
 
 def screen_cursor_forward(amt: int) -> None:
-    write(CSI + '%sC' % amt)
+    write(f'{CSI}{amt}C')
 
 
 def screen_save_cursor() -> None:
@@ -58,105 +58,105 @@ def screen_restore_cursor() -> None:
 
 
 def screen_cursor_back1(amt: int) -> None:
-    write(CSI + '%sD' % amt)
+    write(f'{CSI}{amt}D')
 
 
 def screen_save_modes() -> None:
-    write(CSI + '?s')
+    write(f'{CSI}?s')
 
 
 def screen_restore_modes() -> None:
-    write(CSI + '?r')
+    write(f'{CSI}?r')
 
 
 def screen_designate_charset(which: int, to: int) -> None:
     w = '()'[int(which)]
     t = chr(int(to))
-    write('\033' + w + t)
+    write(f'\x1b{w}{t}')
 
 
 def select_graphic_rendition(*a: int) -> None:
-    write(CSI + '%sm' % ';'.join(map(str, a)))
+    write(f'{CSI}{";".join(map(str, a))}m')
 
 
 def screen_cursor_to_column(c: int) -> None:
-    write(CSI + '%dG' % c)
+    write(f'{CSI}{c}G')
 
 
 def screen_cursor_to_line(ln: int) -> None:
-    write(CSI + '%dd' % ln)
+    write(f'{CSI}{ln}d')
 
 
 def screen_set_mode(x: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(x) + 'h')
+    write(f'{CSI}{"?" if private else ""}{x}h')
 
 
 def screen_save_mode(x: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(x) + 's')
+    write(f'{CSI}{"?" if private else ""}{x}s')
 
 
 def screen_reset_mode(x: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(x) + 'l')
+    write(f'{CSI}{"?" if private else ""}{x}l')
 
 
 def screen_restore_mode(x: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(x) + 'r')
+    write(f'{CSI}{"?" if private else ""}{x}r')
 
 
 def screen_set_margins(t: int, b: int) -> None:
-    write(CSI + '%d;%dr' % (t, b))
+    write(f'{CSI}{t};{b}r')
 
 
 def screen_indexn(n: int) -> None:
-    write(CSI + '%dS' % n)
+    write(f'{CSI}{n}S')
 
 
 def screen_delete_characters(count: int) -> None:
-    write(CSI + '%dP' % count)
+    write(f'{CSI}{count}P')
 
 
 def screen_push_colors(which: int) -> None:
-    write(CSI + '%d#P' % which)
+    write(f'{CSI}{which}#P')
 
 
 def screen_pop_colors(which: int) -> None:
-    write(CSI + '%d#Q' % which)
+    write(f'{CSI}{which}#Q')
 
 
 def screen_report_colors() -> None:
-    write(CSI + '#R')
+    write(f'{CSI}#R')
 
 
 def screen_repeat_character(num: int) -> None:
-    write(CSI + '%db' % num)
+    write(f'{CSI}{num}b')
 
 
 def screen_insert_characters(count: int) -> None:
-    write(CSI + '%d@' % count)
+    write(f'{CSI}{count}@')
 
 
 def screen_scroll(count: int) -> None:
-    write(CSI + '%dS' % count)
+    write(f'{CSI}{count}S')
 
 
 def screen_erase_in_display(how: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(how) + 'J')
+    write(f'{CSI}{"?" if private else ""}{how}J')
 
 
 def screen_erase_in_line(how: int, private: bool) -> None:
-    write(CSI + ('?' if private else '') + str(how) + 'K')
+    write(f'{CSI}{"?" if private else ""}{how}K')
 
 
 def screen_delete_lines(num: int) -> None:
-    write(CSI + str(num) + 'M')
+    write(f'{CSI}{num}M')
 
 
 def screen_cursor_up2(count: int) -> None:
-    write(CSI + '%dA' % count)
+    write(f'{CSI}{count}A')
 
 
 def screen_cursor_down(count: int) -> None:
-    write(CSI + '%dB' % count)
+    write(f'{CSI}{count}B')
 
 
 def screen_carriage_return() -> None:
@@ -176,11 +176,11 @@ def screen_backspace() -> None:
 
 
 def screen_set_cursor(mode: int, secondary: int) -> None:
-    write(CSI + '%d q' % secondary)
+    write(f'{CSI}{secondary} q')
 
 
 def screen_insert_lines(num: int) -> None:
-    write(CSI + '%dL' % num)
+    write(f'{CSI}{num}L')
 
 
 def draw(*a: str) -> None:
@@ -188,7 +188,7 @@ def draw(*a: str) -> None:
 
 
 def screen_manipulate_title_stack(op: int, which: int) -> None:
-    write(CSI + '%d;%dt' % (op, which))
+    write(f'{CSI}{op};{which}t')
 
 
 def report_device_attributes(mode: int, char: int) -> None:
@@ -197,21 +197,22 @@ def report_device_attributes(mode: int, char: int) -> None:
         x += chr(char)
     if mode:
         x += str(mode)
-    write(CSI + x + 'c')
+    write(f'{CSI}{x}c')
 
 
 def screen_decsace(mode: int) -> None:
-    write(CSI + str(mode) + '*x')
+    write(f'{CSI}{mode}*x')
 
 
 def screen_set_8bit_controls(mode: int) -> None:
-    write('\x1b ' + ('G' if mode else 'F'))
+    write(f'\x1b {"G" if mode else "F"}')
 
 
 def write_osc(code: int, string: str = '') -> None:
     if string:
-        string = ';' + string
-    write(OSC + str(code) + string + '\x07')
+        write(f'{OSC}{code};{string}\x07')
+    else:
+        write(f'{OSC}{code}\x07')
 
 
 set_dynamic_color = set_color_table_color = process_cwd_notification = write_osc
@@ -235,7 +236,7 @@ def clipboard_control(payload: str) -> None:
         clipboard_control_pending += data.lstrip(';')
         payload = clipboard_control_pending
         clipboard_control_pending = ''
-    write(OSC + payload + '\x07')
+    write(f'{OSC}{payload}\x07')
 
 
 def replay(raw: str) -> None: