If you work for the agent as a employee, you agent will deduct EI, CPP etc from your pay check and you will recevie form T4. In this case you are not a contractor, you are an employee of your agent and only work on your agent's contract assigements which is a contract between your agent and the working company. For the status of income tax, you are dealing with your agent as an employee/employer relationship, nothing to do as a contractor.