Claude Code: format .md files on save

settings.json

"PostToolUse": [
  {
    "matcher": "Edit|Write",
    "hooks": [
      {
        "type": "command",
        "command": "bash -c 'FILE=$(cat | jq -r \".tool_input.file_path // empty\"); if [[ \"$FILE\" == *.md ]] && command -v prettier &>/dev/null; then prettier --write --prose-wrap preserve \"$FILE\" 2>/dev/null || true; fi'"
      }
    ]
  }
]

npm install -g prettier