Permanent establishment rules under the Brazil DTAA define fixed places, service presence, agency links, and preparatory activity exclusions. Permanent establishment under the Brazil DTAA is a fixed place of business through which an enterprise carries on business, including specified places such as branches, offices, factories, workshops, natural resource extraction sites, and construction or assembly projects exceeding six months. The concept also extends to service furnishing through employees or other personnel when activities continue for more than 183 days in any 12-month period. Exclusions apply for preparatory or auxiliary activities, subject to anti-fragmentation rules, and agency PE rules apply where a person habitually concludes contracts or plays the principal role in their routine conclusion, unless acting as an independent agent.