Various approaches (deontological, consequentialist, virtue-oriented, and pragmatic) may be taken toward establishing the criteria for an ideal moral agent. Various approaches may also be taken toward establishing the principles that should guide an ideal moral agent.
Presumably, the ideal moral agent will be an ideal observer (an impartial, fully informed, and competent observer) of situations in which moral decisions must be made. The ideal moral agent will also be an ideal moral observer (an observer who observes from a moral, but not moralistic, viewpoint, and who can fully recognize, understand, and respond to the moral implications of whatever she observes). Thus, she will be an ideal evaluator of (and if necessary, an ideal participant in) those situations with which she is confronted. If the ideal moral agent is truly moral, then she will also embody all the moral virtues (such as wisdom, understanding, empathy, compassion, honesty, integrity, impartiality, diligence, discipline, and humility) that should belong to an ideal moral agent.
Any moral judgment made by an ideal moral agent will, of course, be an ideal judgment (impartial, correct, apt, adroit, and fully justified). An apt judgment may be one that is suited to the agent's own interpretive and judgmental skills and to the particular situation. An adroit judgment may be one that is deft, resourceful, nimble, and skillful. According to Kantian ethics, any moral judgment made by an ideal moral agent will also be capable of being universalized (being taken as a universal guide for moral conduct).
If we accept the ideal moral agent as a role model for our own conduct as moral agents, then any decisions that we make should be those that would be made by an ideal moral agent if she were acting in the same situation. In examining the rightness or wrongness of our own moral conduct, we may ask ourselves if our actions were the same as those that would have been performed by an ideal moral agent if she were acting in the same situation. Such comparisons between ourselves and the ideal moral agent, of course, presuppose that there is an ideal mode of moral conduct for (or an ideal moral response to) a given situation. If there is no ideal mode of moral conduct for a given situation, or if no such mode of conduct is possible in a given situation, then adherence to a moral ideal (or conformity to the moral standards that would be fulfilled by an ideal moral agent) may require that we perform the best (or most right) action that we are capable of performing in that situation.
If we attempt to emulate an ideal moral agent, we will, of course, set ourselves up for the possibility of failure. But the willing acceptance of our own moral imperfections and of the resultant possibility of our failure to meet an ideal standard of moral conduct is, in itself, a morally virtuous action. It may be the case that only by attempting to do what an ideal moral agent would do in a particular situation can we ever hope to transcend our own moral faults and imperfections.
The ideal moral agent may also be conceptualized as an ideal speaker of a moral language. The ideal speaker of a moral language will, of course, be fully competent in the rules and usage of that language (she will have a full command of the vocabulary and syntax of that language, and she will be fully proficient in the use of that language for social and communicative purposes). The ideal speaker's use of the moral language will also be commensurate with her knowledge of the language, and she will have an ideal knowledge without any perceptible faults or deficiencies (no lack of correspondence will be seen between her knowledge of the rules and usage of the language and her ability to use the language for social and communicative purposes).
If we share a moral language, then the ideal speaker of that language may be seen as a role model for our moral conduct as communicators. Insofar as we share a moral language, we also share a means of moral expression, and we become members of a linguistic (expressive and interpretive) community.
An objection that may be made to the concept of an ideal moral agent is that moral decisions may be more appropriately made by adopting the viewpoint of a real, rather than an ideal, observer. If the ideal moral agent is merely an abstract model, of what use is that model for moral decision-making in real situations? Presumably, our moral conduct will be truly virtuous when it conforms to moral standards or expectations that are both real and ideal.