Cmd+Backspace and Opt+Backspace silently dropped in Warp (kitty mode legacy-byte fallback needed in opentui) #25267

Summary

When running opencode in Warp terminal, Cmd+Backspace and Opt+Backspace do nothing in the chat input box. They work as expected (delete-to-line-start / delete-word-backward) in Ghostty.

Root cause: Warp's kitty keyboard implementation is inconsistent — it sends legacy single-byte control codes (\x15, \x17) for Cmd/Opt+Backspace even when kitty mode is active, while sending CSI u sequences for plain Ctrl+U / Ctrl+W. opentui's parser, after negotiating kitty mode, appears to drop these legacy bytes for keys that should arrive as CSI u.

This is partly a Warp bug (filed at warpdotdev/Warp), but a robustness fix in opentui — accepting legacy bytes alongside CSI u in kitty mode — would unblock affected users immediately.

Reproduction

1. Open Warp terminal (current stable, kitty keyboard protocol enabled)
2. Run opencode (v1.14.31)
3. In the chat input, type hello world test
4. Press Cmd+Delete — nothing happens (expected: line cleared)
5. Press Opt+Delete — nothing happens (expected: word deleted)
6. Press Ctrl+U — line clears ✓
7. Press Ctrl+W — word deletes ✓

Evidence

Captured the actual byte sequences Warp sends opencode (with kitty keyboard mode pushed via \x1b[>1u):

Cmd+Delete  → 15                              (legacy \x15, single byte)
Opt+Delete  → 17                              (legacy \x17, single byte)
Ctrl+U      → 1b 5b 31 31 37 3b 35 75        (= ESC[117;5u, kitty CSI u)
Ctrl+W      → 1b 5b 31 31 39 3b 35 75        (= ESC[119;5u, kitty CSI u)

Test script used:

cat > /tmp/keytest.py << 'PY'
import sys, tty, termios, os
sys.stdout.write('\x1b[>1u'); sys.stdout.flush()
fd = sys.stdin.fileno()
old = termios.tcgetattr(fd)
try:
    tty.setraw(fd)
    while True:
        c = os.read(fd, 1)
        sys.stdout.write('%02x ' % c[0]); sys.stdout.flush()
        if c == b'q': break
finally:
    termios.tcsetattr(fd, termios.TCSADRAIN, old)
    sys.stdout.write('\x1b[<u\r\n')
PY
python3 /tmp/keytest.py

Suggested fix

In opentui's keypress parser (packages/core/src/parse.keypress.ts per librarian analysis), when kitty mode is active, also accept legacy single-byte control codes as fallback:

• \x15 → { name: "u", ctrl: true }
• \x17 → { name: "w", ctrl: true }
• \x1b\x7f → { name: "backspace", meta: true }

These already parse correctly in non-kitty mode. The fix is making sure kitty mode doesn't gate them out.

Environment

• macOS
• Warp terminal (stable, kitty support enabled)
• opencode v1.14.31

Workarounds

• Use Ctrl+U / Ctrl+W (works, sent as proper CSI u that opentui parses)
• Use Ghostty (correctly encodes Cmd/Opt+Backspace as CSI u)

Related

• opentui#685 — Warp sends modified keys as plain control keys
• Feature: Allow custom keybindings to send raw hex codes / OpenCode SHIFT+ENTER Fix. warpdotdev/warp#8462 — kitty keyboard protocol gaps
• Support modifyOtherKeys and/or Kitty's keyboard protocol warpdotdev/warp#2037 — kitty protocol support