This research investigates the morpho-syntactic behaviour of the Arabic complementizer ʔinn in a range of Arabic varieties (Modern Standard Arabic, Jordanian Arabic, and Lebanese Arabic). It essentially argues that this complementizer shares (not donates or keeps, pace Ouali 2008, 2011) its unvalued $\unicode[STIX]{x1D719}$-features with its complement $\text{T}^{0}$, something that makes ʔinn and $\text{T}^{0}$ separate agreeing heads. An inflectional suffix attached to ʔinn is treated as a PF reflex (i.e. an overt morphological realization) of valuation of ʔinn’s unvalued $\unicode[STIX]{x1D719}$-features or lack thereof. This research also argues that the occurrence of such an inflectional suffix is ruled by the postulated Agree Chain Record, an interface condition that demands an Agree relation to have a PF reflex, called a Record (i.e. an overt Case marking on the goal or, if not, a $\unicode[STIX]{x1D719}$-affix on the probe). This way, we account for the complementary distribution of overt Case and $\unicode[STIX]{x1D719}$-Agree in Arabic. We also show how a host of other phenomena, including word order agreement asymmetries in Modern Standard Arabic and lack of such asymmetries in Arabic vernaculars, fares well with this view.