On Thursday, OpenAI introduced a streamlined version of its agentic coding tool Codex, following the launch of the latest main model earlier this month. This new variant, called GPT-5.3-Codex-Spark, is characterized as a “smaller version” optimized for quicker inference. To enable this speed, OpenAI has incorporated a specialized chip from its hardware collaborator Cerebras, signaling a deeper integration within the company’s physical infrastructure.

The collaboration between Cerebras and OpenAI was first revealed last month, when OpenAI disclosed a multi-year agreement valued at over $10 billion. “Integrating Cerebras into our mix of compute solutions is all about making our AI respond much faster,” the company stated previously. OpenAI now refers to Spark as the “first milestone” in this partnership.

Designed for fast, real-time collaboration and “rapid iteration,” Spark will run on Cerebras’ Wafer Scale Engine 3 (WSE-3). This third-generation waferscale megachip is equipped with 4 trillion transistors. OpenAI positions the lightweight tool as a “daily productivity driver” aimed at assisting with quick prototyping, in contrast to the more extensive tasks handled by the original GPT-5.3 model.

Currently, Spark is available in a research preview for ChatGPT Pro users within the Codex app. Ahead of the announcement, CEO Sam Altman appeared to allude to the new model in a tweet, saying, “We have a special thing launching to Codex users on the Pro plan later today. It sparks joy for me.”

In its official release, OpenAI stressed that Spark is engineered for minimal latency on Codex. “Codex-Spark is the first step toward a Codex that works in two complementary modes: real-time collaboration when you want rapid iteration, and long-running tasks when you need deeper reasoning and execution,” the company explained. It added that Cerebras’ chips are particularly effective for “workflows that demand extremely low latency.”

Although Cerebras has operated for more than ten years, it has gained significant prominence in the tech industry during the AI era. Just last week, the company reported raising $1 billion in new funding at a $23 billion valuation. Cerebras has also previously expressed plans to pursue an initial public offering.

“What excites us most about GPT-5.3-Codex-Spark is partnering with OpenAI and the developer community to discover what fast inference makes possible - new interaction patterns, new use cases, and a fundamentally different model experience,” said Sean Lie, CTO and co-founder of Cerebras. “This preview is just the beginning.”