Helen Liddell, Labour's education spokeswoman, has already outlined how a loose "compact" will ensure better liaison between home and school but Mr Robertson last Friday raised the ante by floating the idea of a legal contract.
The forthcoming Government White Paper on Scottish education will spell out how the Conservatives' contract will work.
Outlining his proposals, Mr Robertson said: "One option is to give contract arrangements statutory force, for example, to give them a role in the management of exclusion procedures and a direct expression of the important role parents have in the behaviour of their children."
Contracts would embody a set of rules governing behaviour, rewards and sanctions. "Generally, home-to-school contracts involve pupils, parents and the school agreeing a set of rights and responsibilities which they undertake to use to guide their approach to day to day activities in the school. They are two-way: giving rights and responsibilities to both pupils and staff. They are highly individual, reflecting the particular circumstances of participating schools," Mr Robertson said.