فَإِذَا عَايَنَ الْبَيْتَ كَبَّرَ وَهَلَّلَ.
Translation: When he sees the House, he says takbīr and tahlīl.
ʿĀyana means to see directly. Takbīr declares Allah's greatness, while tahlīl affirms His oneness.
The quoted text does not prescribe one mandatory lengthy supplication at this moment. It names two forms of remembrance.