Tripartiate Agreement

I am selling my Flat booked with a Builder to another buyer with consent to builder. I am in other city and m flat is in kolkata. I did not completed the registry of my flat and paid 90% amount to Builder through home loan. Now the triaptriate agreement between 3 of us on Rs 10 stamp paper sufficient? Builder has initiated this agreement and on Stamp paper we all 3 parties have signed and the information is limited to this: Heading(Tripatriate agreement dated xxxx16) M/S xyz builder addres abc, ( hereafter called as the VENDOR which expression shall unless repugnant to the subject or context or meaning thereof be deemed to include its sucessors and assigns. The remaining information about buyser and seller details mentioind on atatched palin whaite paper with other details like cost and how much to pay to builder and seller(myself) by the new buyer. Is that sufficient to have legal obligation for any future complexity ? Stamp paper is notorised.(is there any online way to verify its validity?) Pls help. Regards, Manoj