Fix Kitty terminal stealing Ctrl+_ (undo) from Claude Code — remap splits and pass through the keypress

kitty-claude-code-ctrl-underscore-undo-fix.conf

# ─────────────────────────────────────────────────────────────
#  Kitty + Claude Code: Fix Ctrl+_ (Undo) Conflict
# ─────────────────────────────────────────────────────────────
#
#  PROBLEM:
#    Kitty's default ctrl+shift+- mapping (decrease font size)
#    intercepts Ctrl+_ (since _ is Shift+-), preventing Claude
#    Code from receiving its "undo prompt edit" shortcut.
#
#  SOLUTION:
#    Add these lines to your ~/.config/kitty/kitty.conf
#    Then reload with Ctrl+Shift+F5.
#
# ─────────────────────────────────────────────────────────────

# Pass ctrl+shift+- (= ctrl+_) through to apps as 0x1F (terminal undo byte)
# This fixes Claude Code's "undo prompt edit" shortcut
map ctrl+shift+- send_text all \x1f

# If you were using ctrl+shift+- for splits, move it to ctrl+alt+-
# Horizontal split (stacked)
map ctrl+alt+- launch --location=hsplit --cwd=current

# Vertical split (side by side) — unchanged, just here for reference
# map ctrl+shift+\ launch --location=vsplit --cwd=current

# Zoom out still works via ctrl+- (no shift)
# map ctrl+minus change_font_size all -1.0