fix: apply Ghostty terminal colors via AppleScript from TTY-less subprocesses

[mattschwarz]

Summary

• Add Ghostty terminal-color support via AppleScript (osascript), mirroring the iTerm2 approach in fix: apply iTerm2 terminal colors via AppleScript from Claude Code hook subprocesses #2.
• Write the skin palette into Ghostty's config file inside a delimited managed block, then trigger an out-of-band reload_config over Apple Events — no TTY required.
• Guarded to macOS + Ghostty; a silent no-op everywhere else.

Problem

Claude Code runs hook/tool subprocesses without a controlling terminal (deliberate, as of v2.1.139). Both standard color-delivery paths fail:

• /dev/tty — Device not configured (no controlling terminal in the subprocess)
• OSC via stdout — Claude Code's TUI renderer strips the leading ESC byte before output reaches the emulator, so sequences arrive as inert text

This is the same root cause #2 fixes for iTerm2. This PR covers Ghostty.

Solution

Ghostty (1.3.1) ships an AppleScript dictionary (NSAppleScriptEnabled, Ghostty.sdef) exposing a perform action command. osascript reaches Ghostty over Apple Events, bypassing the PTY entirely, so it works from any subprocess regardless of TTY availability.

Ghostty's dictionary has no per-session color properties (unlike iTerm2), so colors are applied by writing them into Ghostty's config file and reloading:

osascript -e 'tell application "Ghostty" to perform action "reload_config" on (terminal 1 of front window)'

• activate.sh writes background, foreground, cursor-color, and the ANSI palette = 0..7 into a delimited managed block in ${XDG_CONFIG_HOME:-$HOME/.config}/ghostty/config, preserving any user config outside the markers, then reloads.
• deactivate.sh strips the managed block (removing the file entirely if it held only our block) and reloads, restoring Ghostty defaults.

Files changed

• engine/activate.sh — write managed Ghostty color block + AppleScript reload
• engine/deactivate.sh — remove managed block + AppleScript reload on reset/exit

Testing

1. Open Claude Code in Ghostty on macOS.
2. /skin mission-control — background → deep navy (#0B1120), foreground → amber (#FFB000), immediately.
3. /skin nebula — background → deep purple (#0E0520).
4. /skin reset — colors restored to Ghostty defaults.

Out-of-band path directly (works with no TTY attached):

osascript -e 'tell application "Ghostty" to perform action "reload_config" on (terminal 1 of front window)'

Known limitations / notes

• macOS + Ghostty only. Guarded on uname == Darwin and Ghostty env detection (TERM_PROGRAM=ghostty / GHOSTTY_RESOURCES_DIR). Other terminals: silent no-op.
• Colors are global. Ghostty's config applies to all windows/surfaces, so every Ghostty window recolors — not just the Claude session's surface. Ghostty's dictionary exposes no per-surface color properties (iTerm2 does, which is why fix: apply iTerm2 terminal colors via AppleScript from Claude Code hook subprocesses #2 can scope per session).
• Requires the standard macOS Automation permission to control Ghostty (granted once via the TCC prompt).
• The managed block is delimited by # >>> claude-skins / # <<< claude-skins; anything outside the markers is preserved.

🤖 Generated with Claude Code