macmd-autoopen.sh

#!/bin/bash
# Open newly written Markdown files in MacMD Viewer, in the background.
#
# Wired as a PostToolUse(Write) hook. Exits silently and successfully on every
# path that is not "a real .md file was just written on a Mac with MacMD
# installed", so it can never interrupt a session.
#
# The switch is two marker files, so that this plugin and the script served at
# macmdviewer.com/setup agree on the same convention:
#
#   ~/.claude/.macmd-autoopen      exists -> ON  (the setup script's convention)
#   ~/.claude/.macmd-autoopen-off  exists -> OFF
#   neither                               -> ON  (installing the plugin is the opt-in)
set -uo pipefail

BUNDLE_ID="com.arthur.MarkdownViewer"

if [ ! -f "$HOME/.claude/.macmd-autoopen" ] \
   && [ -f "$HOME/.claude/.macmd-autoopen-off" ]; then
  exit 0
fi

[ "$(uname -s)" = "Darwin" ] || exit 0

payload="$(cat)"
file="$(printf '%s' "$payload" | python3 -c 'import sys, json
try:
    print(json.load(sys.stdin).get("tool_input", {}).get("file_path", ""))
except Exception:
    pass' 2>/dev/null)"
[ -n "$file" ] || exit 0

case "$file" in
  *.md|*.markdown) ;;
  *) exit 0 ;;
esac

# Machinery, not documentation: agent memory, dependencies, build output, temp.
case "$file" in
  */memory/*|*/MEMORY.md|*/node_modules/*|*/vendor/*|*/.build/*|*/build/*|\
  */DerivedData/*|*/.next/*|*/dist/*|*/target/*|*/.venv/*|*/site-packages/*|\
  /tmp/*|/private/tmp/*|/private/var/folders/*)
    exit 0 ;;
esac

[ -f "$file" ] || exit 0

# -g keeps focus where it is: the file appears, the terminal keeps the cursor.
# If MacMD is not installed, `open` fails and the plugin is simply a no-op —
# no error, no message, nothing to uninstall.
/usr/bin/open -g -b "$BUNDLE_ID" "$file" >/dev/null 2>&1 || true
exit 0