code-davinci-002 (cd2) is the base model of GPT-3.5.
architecture
code-davinci-002 has a max context window of 8000 tokens. It is capable of generating infills when passed a suffix parameter.
release and access
code-davinci-002 was available to some users since early 2022. It was a "beta" model and free to use, but it was not widely known that it was the GPT-3.5 base model. code-davinci-002 was removed from the API for most users in March 2023.
Researchers and creative writers can apply for access to an unofficial code-davinci-002 proxy.