OpenAI Harmony OpenAI's response format for its open-weight model series gpt-oss Try gpt-oss | Learn more | Model card The gpt-oss models were trained on the harmony response format for defining conversation structures, generating reasoning output and structuring function calls. If you are not using gpt-oss directly but through an API or a provider like Ollama, you will not have to be concerned about this as your inference solution will handle the formatting. If you are building your own inferen...