A user was able to use an OpenAI Codex skill to create tasks in Linear, and then instruct Codex to implement and complete all of those tasks overnight.

OpenAI's frontier models, such as the one referred to as "GPT 5.4," are capable of analyzing or migrating codebases containing millions of lines of code.

OpenAI has a model named "Codex Spark" designed for rapid ideation and iteration, achieving an average speed of 1,200 tokens per second.