How can a partnership contract be drafted for opening an engineering office between two partners, such that no party is harmed, given the difference in their tasks and specializations, and how can the partnership percentage be determined if an equal split is not fair?

It is permissible for you to establish a partnership of labor (sharikat abdan) between yourselves, in which you both work with your bodies without capital, and you divide the profits equally or disproportionately according to your agreement. This is a partnership where the partners work with their own hands and divide what they earn, and it includes artisans, engineers, and doctors. The proof of its permissibility is what Abu Dawud and Al-Athram narrated from Ibn Mas'ud regarding his partnership with Ammar and Sa'd on the Day of Badr, and the Prophet, peace and blessings be upon him, approved them for that. This type of partnership is permissible and lawful according to the majority of scholars. It is not a condition for the partners to have equal shares in the profit; rather, it is according to the agreement, because profit is related to work, and it is permissible for the partners to differ in their work.