The Sri Vaishnava sect has two sub-sects, Thenkalai and Vadakalai. Vadakalais follow the teachings of Vedanta Desikan, whereas Thenkalais follow the teachings of Pillai Lokacharya. Now the Vedanta Desika Divya Charitram, which you can read here, is a biography of Vedanta Desikan attributed to Dvitiya Brahmatantra Svatantra Jeeyar, who was Vedanta Desikan’s shishya’s shishya. But I have reason to believe that it’s not an authentic work by him. Let me explain.
This excerpt from the Vedanta Desika Charitram contains an odd account of a debate between Vedanta Desikan and a scholar from Sri Rangam named Tuvarapati Kavalar, wherein Vedanta Desikan repudiates the various teachings in his works now associated with Vadakalais and adopts the beliefs of Thenkalais. In some cases he says that he now realizes that something he wrote in his works was wrong, and in other cases he says that while his works may seem to say one thing they actually mean something else. This strikes me as implausible, and seems like it was written to promote the notion that Vedanta Desikan was really a Thenkalai in his beliefs.
But my question is, are there any other works that mention Vedanta Desikan debating someone named Tuvarapati Kavalar? That may help determine whether this work is authentic or not.
I haven't found any references to Tuvarapati Kavalar at first glance. His name means "guardian of Dwaraka", and it's a name of Krishna, if that helps.