CRC Cards Can Be Used as Lightweight Documentation
Although many discard CRC cards after they’ve worked through collaborations, CRC card-level descriptions can be useful to document a design. While agile developers favor working software over comprehensive documentation, CRC cards are hardly comprehensive documentation. But they can provide simple introductions to complex designs. Last year I worked with a team to develop two-page overview documents for important subsystems and components—design elements were informally drawn on the front, responsibilities were listed on the back. I know of others who directly add this conceptual documentation to their codebase.
CRC card-level descriptions that document a design should include well-formed verb phrases to describe actions and be consistent in their level of detail. Yet they need not tell everything—only what you want to highlight or emphasize.