In this Article, Richard Painter uses contractarian economic theory to demonstrate general trends in professional responsibility rules, including gradual migration away from standards and toward defined rules and increased use of default rules and opt-in rules. Many rules, however, remain broad standards, and immutable rules remain the principal mechanism for regulating conduct that affects third parties. This Article discusses how additional default rules and opt-in rules, if carefully chosen with protection of third parties in mind, could enrich professional responsibility codes enormously. This Article also proposes that the American Bar Association more clearly define opt-out mechanisms in existing default rules and in some cases make them easier to use earlier in representation of clients. In other cases, aspirational rules, including ethical considerations similar to those in the Model Code, could reinvigorate reputational enforcement of ethics norms, particularly if coupled with disclosure of information about lawyer compliance. Finally, this Article proposes that law firms be encouraged or perhaps required to adopt their own codes of professional responsibility. Law firm codes would fill gaps in the law, address agency problems within law firms, and enhance the quality of feedback that lawyers give to each other about ethics within firms.