New harmony chat
OpenAI Releases 39 Harmony
OpenAI just dropped their new Harmony format with the gpt-oss models, introducing a completely different approach to structuring reasoning and tool calls compared to the ChatML format we've been using with models like Qwen3. OpenAI's Harmony format represents a significant evolution in conversation structuring for language models, particularly designed for the gpt-oss models. While ChatML brought structure to LLM interactions, Harmony takes this several steps further by introducing sophisticated features for reasoning, tool use, and multi-channel communication. This tutorial explores why Harmony is a superior choice for modern agentic AI applications. ChatML Limitation: All assistant responses are unified, mixing reasoning with final answers. This hierarchy resolves instruction conflicts predictably and separates concerns cleanly. Harmony: Maintains context across tool calls within reasoning chains:. ChatGPT
Discover Anthropic's upcoming Harmony feature for individual chats, enabling codebase folder integration. OpenAI has launched Harmony, a mandatory new response format for its gpt-oss models, designed to structure agentic workflows with dedicated developer tools. OpenAI today released Harmony, a new and mandatory response format for its new gpt-oss open-weight models , fundamentally changing how developers interact with them. This gives developers granular control and makes building complex AI agents more transparent and reliable. This move signals a strategic pivot to re-engage the open-source community and establish a competitive standard in a market increasingly populated by powerful alternatives. At its core, Harmony is a chat template , a specific set of rules and special tokens that structure the conversation between a user and the model. New Harmony folder feature
. Anthropic seems to be working on enabling the Harmony feature for individual chats. The new feature has been spotted in development and would appear as a new folder icon on the homepage when you are about to start a chat. This folder button opens a pop-up that is still in progress, as it currently only shows placeholders. However, the implementation does not seem to be finalized yet. In my experience, I got rate-limited quickly when testing the feature. It appears that Claude makes a significant number of API calls to transfer data, suggesting it might become possible to upload folders with larger codebases in the future. 
A zwnj I chat1v1
If you're working with reasoning models or building inference infrastructure, understanding these formats is crucial. What is ChatML? If you're working with reasoning models or building inference infrastructure, understanding these formats is crucial. Today, we're diving deep into both formats with side-by-side comparisons to help you understand what's changed and why it matters! It's essentially an XML-inspired way to structure conversations that evolved from the need to clearly separate different parts of a conversation. Harmony is OpenAI's new response format designed specifically for the gpt-oss models.