Hook scripts fail to send notifications: /dev/tty unavailable in Claude Code subprocess

[JanBrnka]

Problem

Warp plugin hook scripts (Stop, PermissionRequest, Notification, etc.) fail to send OSC 777 notifications because Claude Code spawns hook subprocesses
without a controlling TTY.

warp-notify.sh writes to /dev/tty, which silently fails:

printf '\033]777;notify;%s;%s\007' "$TITLE" "$BODY" > /dev/tty 2>/dev/null || true

The || true masks the error, so hooks appear to succeed but no notification is ever delivered.

Evidence

Process tree shows the hook subprocess has no TTY (??), while the parent claude process does:

PID PPID TTY COMMAND
89386 76147 ?? /bin/zsh -c ... (hook subprocess)
76147 43670 ttys007 claude --resume ...
43670 43508 ttys007 -zsh

Running tty from within a hook confirms: not a tty.

Workaround

Modified warp-notify.sh to find the ancestor process's TTY when /dev/tty is unavailable:

TTY_PATH="/dev/tty"
if ! printf '' > "$TTY_PATH" 2>/dev/null; then
    ANCESTOR_TTY=$(ps -o tty= -p $PPID 2>/dev/null | tr -d ' ')
    if [ -n "$ANCESTOR_TTY" ] && [ "$ANCESTOR_TTY" != "??" ] && [ -e "/dev/$ANCESTOR_TTY" ]; then
        TTY_PATH="/dev/$ANCESTOR_TTY"
    else
        ANCESTOR_TTY=$(ps -o tty= -p $(ps -o ppid= -p $PPID) 2>/dev/null | tr -d ' ')
        if [ -n "$ANCESTOR_TTY" ] && [ "$ANCESTOR_TTY" != "??" ] && [ -e "/dev/$ANCESTOR_TTY" ]; then
            TTY_PATH="/dev/$ANCESTOR_TTY"
        else
            exit 0
        fi
    fi
fi
printf '\033]777;notify;%s;%s\007' "$TITLE" "$BODY" > "$TTY_PATH" 2>/dev/null || true



This fix was tested and confirmed working — notifications are delivered correctly after the change.
Environment

- macOS (Darwin 25.3.0, arm64)
- Warp: v0.2026.05.18.05.32.stable_02
- Claude Code: 2.1.121
- Plugin: warp@claude-code-warp 2.0.0
- WARP_CLI_AGENT_PROTOCOL_VERSION=1