Recognize Esc and other control keys in kitty keyboard mode

Enabling the kitty keyboard protocol for Shift+Enter made terminals
report Esc as CSI 27 u, which the CSI-u parser dropped as KeyUnknown,
so Esc stopped aborting the agent. Map kitty control codepoints
(Esc=27, Tab=9, Backspace=127/8) back to their dedicated keys.

commit: 1cc654ebbfceb15f4f56e61011d1a02ea1825a10
author: patriceckhart · 4mo ago · 2026-06-16 05:46 UTC
parent: ab7fb37
signature: unsigned
refs: tag: v0.2.34

2 files · +32 -0

M packages/tui/input.go +13 -0


@@ -342,9 +342,22 @@ func keyFromModifiedCode(code, mod int) (Key, bool) {
342	342		shift := bits&1 != 0
343	343		alt := bits&2 != 0
344	344		ctrl := bits&4 != 0
	345	+	// Kitty keyboard protocol (CSI ... u) reports control keys as their
	346	+	// codepoints: Esc=27, Enter=13, Tab=9, Backspace=127. Without the
	347	+	// enhanced-mode handling these arrive as raw bytes; with it enabled
	348	+	// they come through here, so map them back to their dedicated keys.
345	349		switch code {
346	350		case 13:
347	351		return Key{Kind: KeyEnter, Shift: shift, Alt: alt, Ctrl: ctrl}, true
	352	+	case 27:
	353	+	return Key{Kind: KeyEsc, Shift: shift, Alt: alt, Ctrl: ctrl}, true
	354	+	case 9:
	355	+	if shift {
	356	+	return Key{Kind: KeyShiftTab, Alt: alt, Ctrl: ctrl}, true
	357	+	}
	358	+	return Key{Kind: KeyTab, Shift: shift, Alt: alt, Ctrl: ctrl}, true
	359	+	case 127, 8:
	360	+	return Key{Kind: KeyBackspace, Shift: shift, Alt: alt, Ctrl: ctrl}, true
348	361		}
349	362		if ctrl {
350	363		switch code {


@@ -342,9 +342,22 @@ func keyFromModifiedCode(code, mod int) (Key, bool) {
342	shift := bits&1 != 0	342		shift := bits&1 != 0
343	alt := bits&2 != 0	343		alt := bits&2 != 0
344	ctrl := bits&4 != 0	344		ctrl := bits&4 != 0
		345	+	// Kitty keyboard protocol (CSI ... u) reports control keys as their
		346	+	// codepoints: Esc=27, Enter=13, Tab=9, Backspace=127. Without the
		347	+	// enhanced-mode handling these arrive as raw bytes; with it enabled
		348	+	// they come through here, so map them back to their dedicated keys.
345	switch code {	349		switch code {
346	case 13:	350		case 13:
347	return Key{Kind: KeyEnter, Shift: shift, Alt: alt, Ctrl: ctrl}, true	351		return Key{Kind: KeyEnter, Shift: shift, Alt: alt, Ctrl: ctrl}, true
		352	+	case 27:
		353	+	return Key{Kind: KeyEsc, Shift: shift, Alt: alt, Ctrl: ctrl}, true
		354	+	case 9:
		355	+	if shift {
		356	+	return Key{Kind: KeyShiftTab, Alt: alt, Ctrl: ctrl}, true
		357	+	}
		358	+	return Key{Kind: KeyTab, Shift: shift, Alt: alt, Ctrl: ctrl}, true
		359	+	case 127, 8:
		360	+	return Key{Kind: KeyBackspace, Shift: shift, Alt: alt, Ctrl: ctrl}, true
348	}	361		}
349	if ctrl {	362		if ctrl {
350	switch code {	363		switch code {

M packages/tui/input_test.go +19 -0


@@ -30,6 +30,25 @@ func TestReaderParsesModifyOtherKeysCtrlC(t *testing.T) {
30	30		}
31	31		}
32	32
	33	+	func TestReaderParsesCSIUEsc(t *testing.T) {
	34	+	k := readKey(t, "\x1b[27u")
	35	+	if k.Kind != KeyEsc {
	36	+	t.Fatalf("Read kind=%v, want esc", k.Kind)
	37	+	}
	38	+	}
	39	+
	40	+	func TestReaderParsesCSIUTabAndBackspace(t *testing.T) {
	41	+	if k := readKey(t, "\x1b[9u"); k.Kind != KeyTab {
	42	+	t.Fatalf("Read kind=%v, want tab", k.Kind)
	43	+	}
	44	+	if k := readKey(t, "\x1b[9;2u"); k.Kind != KeyShiftTab {
	45	+	t.Fatalf("Read kind=%v, want shift-tab", k.Kind)
	46	+	}
	47	+	if k := readKey(t, "\x1b[127u"); k.Kind != KeyBackspace {
	48	+	t.Fatalf("Read kind=%v, want backspace", k.Kind)
	49	+	}
	50	+	}
	51	+
33	52		func TestReaderParsesSGRMouseWheel(t *testing.T) {
34	53		cases := []struct {
35	54		seq string


@@ -30,6 +30,25 @@ func TestReaderParsesModifyOtherKeysCtrlC(t *testing.T) {
30	}	30		}
31	}	31		}
32		32
		33	+	func TestReaderParsesCSIUEsc(t *testing.T) {
		34	+	k := readKey(t, "\x1b[27u")
		35	+	if k.Kind != KeyEsc {
		36	+	t.Fatalf("Read kind=%v, want esc", k.Kind)
		37	+	}
		38	+	}
		39	+
		40	+	func TestReaderParsesCSIUTabAndBackspace(t *testing.T) {
		41	+	if k := readKey(t, "\x1b[9u"); k.Kind != KeyTab {
		42	+	t.Fatalf("Read kind=%v, want tab", k.Kind)
		43	+	}
		44	+	if k := readKey(t, "\x1b[9;2u"); k.Kind != KeyShiftTab {
		45	+	t.Fatalf("Read kind=%v, want shift-tab", k.Kind)
		46	+	}
		47	+	if k := readKey(t, "\x1b[127u"); k.Kind != KeyBackspace {
		48	+	t.Fatalf("Read kind=%v, want backspace", k.Kind)
		49	+	}
		50	+	}
		51	+
33	func TestReaderParsesSGRMouseWheel(t *testing.T) {	52		func TestReaderParsesSGRMouseWheel(t *testing.T) {
34	cases := []struct {	53		cases := []struct {
35	seq string	54		seq string