There are two types of consultants, Trusted Advisors and Trustworthy Partners.
Trusted advisors focus on a client's business goals. They provide an objective perspective and structured thinking that helps clients to think through the right course of action to grow their businesses. Recommendations offer the best course of action with analysis and scenarios with likely consequences. They share responsibilty with the client for the usefulness of their work to the organization.
Trustworthy partners work with clients to fill skill gaps in the organization. They are experts in their field, and clients rely on them to provide the best solution within the constraints and goals that have been determined. Recommendations offer the best solution among a set of considered options, and they share responsibility with the client for making sure that the organization can utilize the recommended solution.
While the scope of the roles is different, both types of consultant have one thing in common. They share in the responsibility for their clients success. If you are a consultant, be prepared for the level of responsibility you are willing to take for for the client to be able to utilize your work. Clients use consultants because they do not have the perspective or skills that the consultant brings to the table. Clients cannot tell the consultant what to do or what needs to be done; if they could, they wouldn't need to hire the consultant in the first place.
If you are a consultant, think about how often you find yourself (or your people) complaining that "the client doesn't know what he wants us to do", or "we'll write the proposal when the client figures out what they are doing". If you're not prepared to help your client to think these issues through, then you may be a monkey in consultants' clothes.