When preparing a tender, signing a contract, or making a purchase order, be careful to check a potential client’s or contractor’s track record. They may be a known litigator.
Your company may keep a record of problem companies.
Preference would be to find an alternative supplier/contractor, or to not pursue the project.
If there is no alternative then you must be extra careful with the wording of the contract. You should also have senoir management review and approve the contract before signing it.