Opening article
Open Responses is a new open inference standard launched by OpenAI and built by the open‑source AI community, backed by Hugging Face. It extends the closed Responses API to allow raw reasoning streams and tool invocation, aiming to replace the legacy Chat Completion format for agentic workloads. The standard defines clear roles for model providers and routers, supports internal and external tools, and normalizes agentic loops for multi‑step tasks.
Open Responses is a new and open inference standard. Initiated by OpenAI, built by the open source AI community, and backed by the Hugging Face ecosystem, Open Responses is based on the Responses API and is designed for the future of Agents. In this blog post, we’ll look at how Open Responses works and why the open source community should use Open Responses.
The era of the chatbot is long gone, and agents dominate inference workloads. Developers are shifting toward autonomous systems that reason, plan, and act over long-time horizons. Despite this shift, much of the ecosystem still uses the Chat Completion format, which was designed for turn-based conversations and falls short for agentic use cases. The Responses format was designed to address these limitations, but it is closed and not as widely adopted. The Chat Completion format is still the de facto standard despite the alternatives.
This mismatch between the agentic workflow requirements and entrenched interfaces motivates the need for an open inference standard. Over the coming months, we will collaborate with the community and inference providers to implement and adapt Open Responses to a shared format, practically capable of replacing chat completions.
Clients that already support the Responses API can migrate to Open Responses with relatively little effort. The main changes involve how reasoning content is exposed:
For Model Providers, implementing the changes for Open Responses should be straightforward if they already adhere to the Responses API specification. For Routers, there is now the opportunity to standardize on a consistent endpoint and support configuration options for customization where needed.
Open Responses builds on the direction OpenAI has set with their Responses API launched in March 2025, which superseded the existing Completion and Assistants APIs with a consistent way to:
Open Responses extends and open-sources the Responses API, making it more accessible for builders and routing providers to interoperate and collaborate on shared interests.
We’ll briefly explore the core changes that impact most community members. If you want to deep dive into the specification, check out the Open Responses documentation .
By providing a consistent, open standard for agentic inference, Open Responses could reduce fragmentation in the industry and improve interoperability between providers and clients.