OpenAI’s rapid GPT-5.3-Codex model moves beyond simple coding tasks – News

OpenAI Group PBC today released a lightweight version of its popular agentic coding tool GPT-5.3-Codex, which is designed for more rapid inference, the process by which artificial intelligence models take actions in response to prompts.

It’s called GPT‑5.3‑Codex‑Spark, and it’s a smaller version of the original GPT‑5.3‑Codex that launched earlier this month. By launching a more streamlined version, OpenAI is taking a cue from Google LLC, which offers the Gemini Flash series of large language models as a faster, lower-cost alternative for applications that don’t need so much processing power.

OpenAI said in a blog post that GPT-5.3-Codex-Spark is the first of its models to run on a dedicated chip from the artificial intelligence chipmaker Cerebras Systems Inc., which partnered with the ChatGPT maker last month. The two companies announced a multiyear agreement that’s worth over $10 billion, and now we know why. At the time, OpenAI said “integrating Cerebras into our mix of compute solutions is all about making our AI respond much faster,” and Spark has become the “first milestone” in that partnership.

The company explained that Spark is powered by Cerebras’ Wafer Scale Engine 3 and designed for swift, real-time collaboration and rapid iteration. The WSE-3 chip is Cerebras’ third-generation AI processor. As with the company’s earlier chips, it’s a massive, dinner plate-sized piece of silicon that boasts more than 4 trillion transistors.

Besides the chip, another of the notable things about Spark is that it was apparently “instrumental in creating itself.” By that, OpenAI means that early versions of the model were used to help debug its own training processes, manage its deployment, diagnose test results and conduct evaluations. “Our team was blown away by how much Codex Spark was able to accelerate its own development,” the company said.

Not just coding

GPT-5.3-Codex-Spark is meant to be a “daily productivity driver” and designed primarily for rapid prototyping, the company explained. That means it can handle more than just basic coding tasks. It’s an AI agent that can perform almost all of the things that developers might do on a computer, the company explained. That includes “debugging, deploying, monitoring, writing PRDs, editing copy, user research, tests, metrics and more,” OpenAI said. In addition, there’s also an emphasis on being able to steer the model mid-task and provide frequent status updates.

As far as performance goes, OpenAI said Spark surpasses the reasoning capabilities of the full-fat GPT-5.2-Codex model and the standard GPT-5.2 model that currently powers ChatGPT. Its outputs are generated at a 25% faster rate, on average. In addition, GPT-5.3-Codex-Spark only consumes around half of the “tokens” used by earlier models when producing certain kinds of outputs. Tokens are the fundamental units of information that AI models use to process and generate data.

On the Terminal-Bench 2.0 benchmark, GPT-5.3-Codex-Spark scored 77.3%, improving on the 64% accuracy level of GPT-5.2-Codex. It also shows similar improvements in game and web development, OpenAI said.

GPT‑5.3‑Codex‑Spark is currently only available to ChatGPT’s paid subscribers, and will also be made available through the company’s application programming interface “soon.” There are no changes to pricing or limits on users compared to the standard GPT-5.3-Codex model.

“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,” OpenAI said. The company added that Cerebras’ chips excel at assisting “workflows that demand extremely low latency.”

Cerebras has emerged as one of the most prominent rivals to Nvidia Corp. in the AI compute business. Last week, the chipmaker announced it had raised an additional $1 billion in funding in a round that raised its value to $23 billion. That’s likely to be its last major funding round, since the company has submitted paperwork for an initial public offering that’s expected to proceed in the first half of this year. Going forward, the chipmaker expects to collaborate much more with OpenAI in future.

“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,” said Cerebras co-founder and Chief Technology Officer Sean Lie. “New interaction patterns, new use cases and a fundamentally different model experience, and this preview is just the beginning.”

Image: OpenAI