diff --git a/internal/ui/form.go b/internal/ui/form.go
index c5693104..39eeb90e 100644
--- a/internal/ui/form.go
+++ b/internal/ui/form.go
@@ -428,6 +428,12 @@ func (m *FormModel) Init() tea.Cmd {
 
 // Update handles messages.
 func (m *FormModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	// Normalize modern CSI-u / modifyOtherKeys sequences (Shift+Enter,
+	// Option+Delete, Cmd+Delete on macOS terminals like Ghostty, WezTerm,
+	// Kitty, and iTerm2 with modifyOtherKeys) into standard tea.KeyMsg
+	// values so the rest of the form sees the keys it already handles.
+	msg = translateModernKey(msg)
+
 	switch msg := msg.(type) {
 	// Handle autocomplete debounce tick - fire the LLM request
 	case autocompleteTickMsg:
diff --git a/internal/ui/form_modern_keys_test.go b/internal/ui/form_modern_keys_test.go
new file mode 100644
index 00000000..b263137d
--- /dev/null
+++ b/internal/ui/form_modern_keys_test.go
@@ -0,0 +1,131 @@
+package ui
+
+import (
+	"testing"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+// These tests verify that the form treats modern CSI-u and modifyOtherKeys
+// sequences the same way it treats their legacy equivalents. They cover the
+// keys reported broken in the bug: Option+Delete, Cmd+Delete, and
+// Shift+Return inside the body/details field.
+
+func newFormForKeyTest(t *testing.T, focused FormField, value string) *FormModel {
+	t.Helper()
+	m := NewFormModel(nil, 100, 50, "", nil)
+	m.focused = focused
+	switch focused {
+	case FieldTitle:
+		m.blurAll()
+		m.titleInput.Focus()
+		m.titleInput.SetValue(value)
+		m.titleInput.CursorEnd()
+	case FieldBody:
+		m.blurAll()
+		m.bodyInput.Focus()
+		m.bodyInput.SetValue(value)
+		m.bodyInput.CursorEnd()
+	}
+	return m
+}
+
+func TestForm_ShiftEnterInsertsNewlineInBody(t *testing.T) {
+	cases := []struct {
+		name string
+		msg  tea.Msg
+	}{
+		{"native KeyEnter", tea.KeyMsg{Type: tea.KeyEnter}},
+		{"kitty CSI-u shift+enter", captureCSI(t, []byte("\x1b[13;2u"))},
+		{"modifyOtherKeys shift+enter", captureCSI(t, []byte("\x1b[27;2;13~"))},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			m := newFormForKeyTest(t, FieldBody, "hello")
+			m.Update(tc.msg)
+			if got := m.bodyInput.Value(); got != "hello\n" {
+				t.Errorf("body = %q, want %q", got, "hello\n")
+			}
+		})
+	}
+}
+
+func TestForm_OptionDeleteDeletesWordInBody(t *testing.T) {
+	cases := []struct {
+		name string
+		msg  tea.Msg
+	}{
+		{"native alt+backspace", tea.KeyMsg{Type: tea.KeyBackspace, Alt: true}},
+		{"kitty CSI-u option+delete", captureCSI(t, []byte("\x1b[127;3u"))},
+		{"modifyOtherKeys option+delete", captureCSI(t, []byte("\x1b[27;3;127~"))},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			m := newFormForKeyTest(t, FieldBody, "hello world foo")
+			m.Update(tc.msg)
+			if got := m.bodyInput.Value(); got != "hello world " {
+				t.Errorf("body = %q, want %q", got, "hello world ")
+			}
+		})
+	}
+}
+
+func TestForm_OptionDeleteDeletesWordInTitle(t *testing.T) {
+	cases := []struct {
+		name string
+		msg  tea.Msg
+	}{
+		{"native alt+backspace", tea.KeyMsg{Type: tea.KeyBackspace, Alt: true}},
+		{"kitty CSI-u option+delete", captureCSI(t, []byte("\x1b[127;3u"))},
+		{"modifyOtherKeys option+delete", captureCSI(t, []byte("\x1b[27;3;127~"))},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			m := newFormForKeyTest(t, FieldTitle, "hello world foo")
+			m.Update(tc.msg)
+			if got := m.titleInput.Value(); got != "hello world " {
+				t.Errorf("title = %q, want %q", got, "hello world ")
+			}
+		})
+	}
+}
+
+func TestForm_CmdDeleteClearsLineInBody(t *testing.T) {
+	cases := []struct {
+		name string
+		msg  tea.Msg
+	}{
+		{"native ctrl+u", tea.KeyMsg{Type: tea.KeyCtrlU}},
+		{"kitty CSI-u cmd+delete", captureCSI(t, []byte("\x1b[127;9u"))},
+		{"modifyOtherKeys cmd+delete", captureCSI(t, []byte("\x1b[27;9;127~"))},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			m := newFormForKeyTest(t, FieldBody, "hello world foo")
+			m.Update(tc.msg)
+			if got := m.bodyInput.Value(); got != "" {
+				t.Errorf("body = %q, want empty", got)
+			}
+		})
+	}
+}
+
+func TestForm_CmdDeleteClearsLineInTitle(t *testing.T) {
+	cases := []struct {
+		name string
+		msg  tea.Msg
+	}{
+		{"native ctrl+u", tea.KeyMsg{Type: tea.KeyCtrlU}},
+		{"kitty CSI-u cmd+delete", captureCSI(t, []byte("\x1b[127;9u"))},
+		{"modifyOtherKeys cmd+delete", captureCSI(t, []byte("\x1b[27;9;127~"))},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			m := newFormForKeyTest(t, FieldTitle, "hello world foo")
+			m.Update(tc.msg)
+			if got := m.titleInput.Value(); got != "" {
+				t.Errorf("title = %q, want empty", got)
+			}
+		})
+	}
+}
diff --git a/internal/ui/key_csi.go b/internal/ui/key_csi.go
new file mode 100644
index 00000000..83cd30c2
--- /dev/null
+++ b/internal/ui/key_csi.go
@@ -0,0 +1,98 @@
+package ui
+
+import (
+	"fmt"
+	"reflect"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+// translateModernKey converts CSI-u and xterm modifyOtherKeys sequences that
+// bubbletea v1 reports as unknownCSISequenceMsg into standard tea.KeyMsg
+// values so the textinput/textarea bindings can act on them. macOS terminals
+// configured with the kitty keyboard protocol or modifyOtherKeys mode 2
+// (Ghostty, WezTerm, modern iTerm2, Kitty) send these sequences for
+// Shift+Enter, Option+Delete, Cmd+Delete, and similar combinations that the
+// user expects to work like in any other macOS text field.
+//
+// If msg is not a recognized CSI sequence, it is returned unchanged.
+func translateModernKey(msg tea.Msg) tea.Msg {
+	seq, ok := csiSequence(msg)
+	if !ok {
+		return msg
+	}
+	if translated, ok := csiKeyMap[seq]; ok {
+		return translated
+	}
+	return msg
+}
+
+// csiSequence extracts the parameter+final portion of an unknown CSI sequence
+// reported by bubbletea (everything after the leading "\x1b["). The underlying
+// type is unexported, so we identify it by its type name and copy the bytes
+// out via reflection.
+func csiSequence(msg tea.Msg) (string, bool) {
+	v := reflect.ValueOf(msg)
+	if !v.IsValid() || v.Kind() != reflect.Slice {
+		return "", false
+	}
+	if fmt.Sprintf("%T", msg) != "tea.unknownCSISequenceMsg" {
+		return "", false
+	}
+	if v.Len() < 3 {
+		return "", false
+	}
+	buf := make([]byte, v.Len())
+	for i := 0; i < v.Len(); i++ {
+		buf[i] = byte(v.Index(i).Uint())
+	}
+	if buf[0] != 0x1b || buf[1] != '[' {
+		return "", false
+	}
+	return string(buf[2:]), true
+}
+
+// csiKeyMap maps the body of CSI sequences (everything after "\x1b[") to a
+// canonical tea.KeyMsg. The mapping covers the two protocols common on macOS:
+//
+//   - Kitty keyboard protocol: "<codepoint>;<modifier>u" where modifier is
+//     1 + sum of (shift=1, alt=2, ctrl=4, super=8, hyper=16, meta=32).
+//   - xterm modifyOtherKeys mode 2: "27;<modifier>;<codepoint>~" where
+//     modifier uses the same convention as xterm CSI ~ sequences (2=shift,
+//     3=alt, 5=ctrl, 9=super, ...).
+//
+// We treat super (Cmd on macOS) and meta the same: line-start/line-end edits
+// for navigation, full-line deletion for delete/backspace.
+var csiKeyMap = map[string]tea.Msg{
+	// Shift+Enter: insert newline. The textarea binds tea.KeyEnter to
+	// InsertNewline, so we route both protocols to KeyEnter.
+	"13;2u":     tea.KeyMsg{Type: tea.KeyEnter},
+	"27;2;13~":  tea.KeyMsg{Type: tea.KeyEnter},
+	"13;6u":     tea.KeyMsg{Type: tea.KeyEnter}, // shift+ctrl+enter
+	"27;6;13~":  tea.KeyMsg{Type: tea.KeyEnter},
+	"13;10u":    tea.KeyMsg{Type: tea.KeyEnter}, // shift+super+enter
+	"27;10;13~": tea.KeyMsg{Type: tea.KeyEnter},
+
+	// Option/Alt+Backspace and Option/Alt+Delete: delete word backward.
+	// textinput/textarea bind alt+backspace to DeleteWordBackward. Most
+	// terminals emit \x1b\x7f for option+delete (already parsed as
+	// alt+backspace), but CSI-u terminals send these forms.
+	"127;3u":    tea.KeyMsg{Type: tea.KeyBackspace, Alt: true},
+	"27;3;127~": tea.KeyMsg{Type: tea.KeyBackspace, Alt: true},
+	"8;3u":      tea.KeyMsg{Type: tea.KeyBackspace, Alt: true},
+	"27;3;8~":   tea.KeyMsg{Type: tea.KeyBackspace, Alt: true},
+
+	// Cmd/Super+Backspace and Cmd/Super+Delete: delete to start of line.
+	// textinput/textarea bind ctrl+u to DeleteBeforeCursor, matching the
+	// macOS convention for Cmd+Delete in native text fields.
+	"127;9u":    tea.KeyMsg{Type: tea.KeyCtrlU},
+	"27;9;127~": tea.KeyMsg{Type: tea.KeyCtrlU},
+	"8;9u":      tea.KeyMsg{Type: tea.KeyCtrlU},
+	"27;9;8~":   tea.KeyMsg{Type: tea.KeyCtrlU},
+
+	// Cmd/Super+Left and Cmd/Super+Right: jump to line start/end. These
+	// aren't in the original report but rounding out the macOS-native set
+	// avoids the same frustration as the user reported for Cmd+Delete.
+	"1;9D": tea.KeyMsg{Type: tea.KeyCtrlA},
+	"1;9C": tea.KeyMsg{Type: tea.KeyCtrlE},
+}
diff --git a/internal/ui/key_csi_test.go b/internal/ui/key_csi_test.go
new file mode 100644
index 00000000..f040933d
--- /dev/null
+++ b/internal/ui/key_csi_test.go
@@ -0,0 +1,150 @@
+package ui
+
+import (
+	"bytes"
+	"io"
+	"reflect"
+	"testing"
+	"time"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+// captureCSI runs bubbletea against raw input bytes so we can grab the
+// unknownCSISequenceMsg it produces (the type is unexported and can only be
+// obtained from the program's message channel).
+func captureCSI(t *testing.T, input []byte) tea.Msg {
+	t.Helper()
+
+	model := &captureCSIModel{}
+	prog := tea.NewProgram(
+		model,
+		tea.WithInput(io.NopCloser(bytes.NewReader(input))),
+		tea.WithOutput(io.Discard),
+	)
+	done := make(chan struct{})
+	go func() {
+		time.Sleep(50 * time.Millisecond)
+		prog.Quit()
+		close(done)
+	}()
+	if _, err := prog.Run(); err != nil {
+		t.Fatalf("program failed: %v", err)
+	}
+	<-done
+	return model.captured
+}
+
+type captureCSIModel struct{ captured tea.Msg }
+
+func (m *captureCSIModel) Init() tea.Cmd { return nil }
+func (m *captureCSIModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	if _, ok := msg.(tea.QuitMsg); ok {
+		return m, tea.Quit
+	}
+	// Capture only the first non-internal message.
+	if m.captured == nil {
+		typ := reflect.TypeOf(msg)
+		if typ != nil && typ.String() != "tea.QuitMsg" {
+			m.captured = msg
+		}
+	}
+	return m, nil
+}
+func (m *captureCSIModel) View() string { return "" }
+
+func TestTranslateModernKey_ShiftEnter(t *testing.T) {
+	cases := []struct {
+		name  string
+		input []byte
+	}{
+		{"kitty CSI-u 13;2u", []byte("\x1b[13;2u")},
+		{"modifyOtherKeys 27;2;13~", []byte("\x1b[27;2;13~")},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			msg := captureCSI(t, tc.input)
+			if msg == nil {
+				t.Fatal("no CSI message captured")
+			}
+			out := translateModernKey(msg)
+			km, ok := out.(tea.KeyMsg)
+			if !ok {
+				t.Fatalf("expected KeyMsg, got %T", out)
+			}
+			if km.Type != tea.KeyEnter {
+				t.Errorf("expected KeyEnter, got %v", km.Type)
+			}
+		})
+	}
+}
+
+func TestTranslateModernKey_OptionDelete(t *testing.T) {
+	cases := []struct {
+		name  string
+		input []byte
+	}{
+		{"kitty CSI-u 127;3u", []byte("\x1b[127;3u")},
+		{"modifyOtherKeys 27;3;127~", []byte("\x1b[27;3;127~")},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			msg := captureCSI(t, tc.input)
+			out := translateModernKey(msg)
+			km, ok := out.(tea.KeyMsg)
+			if !ok {
+				t.Fatalf("expected KeyMsg, got %T", out)
+			}
+			if km.Type != tea.KeyBackspace || !km.Alt {
+				t.Errorf("expected alt+backspace, got type=%v alt=%v", km.Type, km.Alt)
+			}
+			if km.String() != "alt+backspace" {
+				t.Errorf("expected stringification alt+backspace, got %q", km.String())
+			}
+		})
+	}
+}
+
+func TestTranslateModernKey_CmdDelete(t *testing.T) {
+	cases := []struct {
+		name  string
+		input []byte
+	}{
+		{"kitty CSI-u 127;9u", []byte("\x1b[127;9u")},
+		{"modifyOtherKeys 27;9;127~", []byte("\x1b[27;9;127~")},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			msg := captureCSI(t, tc.input)
+			out := translateModernKey(msg)
+			km, ok := out.(tea.KeyMsg)
+			if !ok {
+				t.Fatalf("expected KeyMsg, got %T", out)
+			}
+			if km.Type != tea.KeyCtrlU {
+				t.Errorf("expected ctrl+u, got %v", km.Type)
+			}
+		})
+	}
+}
+
+func TestTranslateModernKey_UnknownSequencePassThrough(t *testing.T) {
+	msg := captureCSI(t, []byte("\x1b[99;99u"))
+	out := translateModernKey(msg)
+	// Unknown CSI sequences must come back unchanged so callers can keep
+	// processing them (or ignore them) as before.
+	if !reflect.DeepEqual(out, msg) {
+		t.Errorf("unknown CSI was modified: got %#v want %#v", out, msg)
+	}
+}
+
+func TestTranslateModernKey_NonCSIPassThrough(t *testing.T) {
+	original := tea.KeyMsg{Type: tea.KeyEnter}
+	if got := translateModernKey(original); !reflect.DeepEqual(got, original) {
+		t.Errorf("regular KeyMsg modified: got %#v want %#v", got, original)
+	}
+
+	if got := translateModernKey(nil); got != nil {
+		t.Errorf("nil msg modified: got %#v", got)
+	}
+}