Users can authorize participating third-party apps to use their ChatGPT plan through “Sign in with ChatGPT,” without sharing an OpenAI API key. OpenAI explicitly states that eligible AI requests in those apps count toward the ChatGPT Work and Codex usage included in the plan; they do not create a separate usage pool. Users can set a weekly percentage cap for each app, and apps can use credits after included usage is exhausted only if the user explicitly enables that option. For heavy Codex users, this means supported tools such as Devin, Warp, Notion, or Vercel may consume the same allowance otherwise available to Codex and Work.