There are several formats associated with Character Cards. Each of them is completely unofficial and more consensus based than definitively declared. Each interface has subtle behavioral differences that can have surprising results. The following specifications are described here to the best of our knowledge.

The Character Card specification, formally called CharaCard contains information about CharaCard version 1, 2, and 3 “standards” as well as a description of how this data is encoded into PNG metadata.

Lorebook specifications are also on the CharaCard page.

While several proposed standards circulate, the only ones we've encountered are the following two:

• CCv2 Lorebook is the lorebook format specified alongside CCv2
• WorldInfo is the undocumented lorebook format used by SillyTavern

• GGUF This is a popular format for quantized LLMs.