The claims are in the writings but everything in the writings is not a claim.
In fact, most of what is in the writings is not a claim. Baha'u'llah's messages and teachings and laws are in the writings but they are not His claims. Do you want some examples?
I cannot show you the claims without bringing up the writings
because the claims are in the writings.
What I mean by a claim is who Baha'u'llah claimed to be, a Messenger of God, the return of Christ and the Father foretold by Isaiah.
Baha’u’llah’s Two Bold Claims
All of which leads us back to Baha’u’llah, who made two very bold claims. First, he declared he was God’s messenger for the next one thousand years, having the same divine authority, the same Holy Spirit, the same divine power, as Moses, Christ, Muhammad, and the other founders of the major world religions:
In the East the light of [God’s] Revelation hath broken; in the West have appeared the signs of His dominion. Ponder this in your hearts, O people, and be not of those who have turned a deaf ear to the admonitions of Him Who is the Almighty, the All-Praised. Let the Breeze of God awaken you. Verily, it hath wafted over the world. Well is it with him that hath discovered the fragrance thereof and been accounted among the well-assured. – Baha’u’llah,
Tablets of Baha’u’llah.
This station, by itself, makes the Baha’i Faith the youngest of the major world religions.
Baha’u’llah made a second and even more challenging claim. He declared he was the promised world messiah foretold in all the prophecies, in all the holy books, of all the religions of the world – the one promised to come on the Day of Judgment, the Day of God, the Time of the End, the End of the World, to establish the kingdom of God on Earth.
Baha’u’llah declared this period in history as the Day of God, the Time of the End. His mission is nothing less than the establishment of this glorious kingdom – the unification of the entire human race into an all-embracing, spiritually mature world civilization based upon divine principles of justice and love, and whose watchword will be unity in diversity.
With this second claim, Baha’is believe that all of the religions of the world have been consummated and fulfilled with the coming of Baha’u’llah.
https://bahaiteachings.org/what-did-bahaullah-teach?