The identification of the text or genre of texts of course closely relates to the identification of the writer. The Shong ston and Jo nang Tibetan translations of
Vaiśvānara as simply me, "fire," yield Agni, as you have indicated, Paul. The Gyijo/rMa Tibetan translation just transliterates
Vaiśvānara rather than translates it. The Rwa Tibetan translation takes
Vaiśvānara as
me bzhin 'jug. This word is found in the
Mahāvyutpatti as Agnive
śa. Bu ston's annotation to
me as found in the
Vimalaprabhā is
me bzhin 'jug gi bu, "son of Agnive
śa," while Jo nang Phyog las rNam rgyal's annotation to
me as found in the
Vimalaprabhā is just
bzhin 'jug gi bu. It seems, then, that there was confusion about this among the Tibetans. Since Agnive
śa is the son of Agni in Hindu mythology, Agnive
śa should be the son of
Vaiśvānara. Agniveśa should not be the same as Vaiśvānara, as Rwa has it. Nor should
Vaiśvānara be the son of Agniveśa, as Bu ston and Jo nang Phyogs las rNam rgyal have it. Unless . . . .
Unless Vaiśvānara refers to a specific writer or speaker different from the mythological Agni. At this point in the Vimalaprabhā commentary on this verse, the author has moved past śruti and smṛti texts, and gone on to texts written by kavi-s. He gives the examples of the Mahābhārata, the Rāmāyaṇa, and the Mārkaṇḍeya Purāṇa. This makes the Upaniṣads per se less likely. We would expect a large text that features meditation and is also poetic. It so happens that the Yogavāsiṣṭha is such a text, and it opens and closes with stories about and by Agniveśya. This book consists of stories within stories, so that the main story proper could be considered a story within the opening story told by Agniveśya to his son Kāruṇya. Walter Slaje has extensively studied this text and its more original version, the Mokṣopaya (which lacks the Agniveśya stories, as was found by Walter). He would be in a position to say more about whether the Yogavāsiṣṭha could be the bhāvanā-dharma referred to in the Vimalaprabhā Kālacakra commentary.
Best regards,
David Reigle
Colorado, U.S.A.