Dear Nagarjuna Reddy,
In this case, the client must have hired the services of a recruitment agency. The latter, in turn, wishes to get the work done from you. Therefore, as per the provisions of the Indian Contract Management Act of 1872, the recruitment agency is a contractor, and you are a sub-contractor.
Keeping aside the legal issues, I recommend asking the recruitment agency to provide a proper Purchase Order (PO) on their company letterhead. Check whether the company is legally registered or not. In the PO, they should mention clearly:
a) The scope of the services
b) How the completeness of services will be measured
c) Quality parameters of the work, if any
d) How the work assignments will be passed on to you? Tell them to make a standardized form and attach it as an appendix to the PO
e) What will be the method of raising an invoice? Tell them to attach the format of the invoice as an appendix to the PO.
f) Method of calculation of payment and credit terms
g) Clause on the non-disclosure of information, if any
Unless you receive a proper PO, do not start your services. There are numerous examples wherein the recruiter was left in the lurch. Ensure that all the terms and conditions are clearly mentioned in the PO.
Your query was on how you will come to know that the candidate you recommended was hired. Point (b) above takes care of your query. Secondly, you will have access to the CV of the candidate. Therefore, you can do independent verification of whether the client has hired a candidate or not. In the PO, ensure that a clause on independent verification is also included.
Thanks,
Dinesh Divekar