GPT-5.3 Instant cuts hallucinations by 26.8% as OpenAI shifts focus from speed to accuracy

OpenAI’s GPT-5.3 Instant — the company’s most widely used model — reduces hallucinations by up to 26.8% compared to its predecessor, prioritizing accuracy and conversational reliability over raw performance gains, OpenAI says.

GPT-5.3 Instant, which is essentially the default and is the most used model for ChatGPT users, also improves on tone, relevance and conversation with fewer refusals. It is available on both ChatGPT and on the API. 

Right now, only the Instant model will be upgraded to 5.3, but the company said it is working on updating the other models under ChatGPT, Thinking, and Pro to 5.3 “soon.” 

GPT-5.3 Instant cuts hallucinations by up to 26.8%

OpenAI ran two internal evaluations: one across higher-stakes domains including medicine, finance, and law; the other drawing on user feedback.

Based on higher-stakes evaluations conducted by the company, GPT-5.3 Instant reduces hallucinations by 26.8% when using the web. It improves reliability by 19.7% when relying on its internal knowledge. User feedback showed a 22.5% decrease in hallucinations when answering queries using web search. 

The company said GPT-5.3 Instant is more reliable because it improved how it balances information from the internet with its own internal training and reasoning. 

“More broadly, GPT-5.3 Instant is less likely to overindex on web results, which previously could lead to long lists of links or loosely connected information. It does a stronger job of recognizing the subtext of questions and surfacing the most important information, especially upfront, resulting in answers that are more relevant and immediately usable, without sacrificing speed or tone,” the company said. 

An example OpenAI gave is when a user asks about the biggest signing in Major League Baseball and its impact. The previous model, GPT-5.2, often defaulted to summarizing search results.

Accuracy overtakes performance as OpenAI’s selling point

With this new release, first on its most used model, OpenAI wants enterprise customers and other ChatGPT users to understand that the battlefront is not just about how performant a model is, but also about how well it can adhere to actual information. Instead of focusing on performance metrics such as speed and token savings, the company is leaning more into GPT-5.3 Instant’s reliability. 

Competitors such as Google and Anthropic also tout greater accuracy in their new models. Anthropic said its new Claude Sonnet 4.6 has fewer hallucinations, while Google was forced to pull its Gemma 3 model after it hallucinated false information about a lawmaker. 

GPT-5.3 Instant dials back refusals and “cringe” tone

“This update focuses on the parts of the ChatGPT experience people feel every day: tone, relevance, and conversational flow. These are nuanced problems that don’t always show up in benchmarks, but shape whether ChatGPT feels helpful or frustrating. GPT-5.3 Instant directly reflects user feedback in these areas,” OpenAI said in a blog post.

GPT-5.3 Instant has a more natural conversation style, moving away from what OpenAI claimed was a “cringe” tone that came across as overbearing and made assumptions about user intent. The company noted that it will ensure the chat platform’s personality is more consistent across updates so users will not experience a tonal shift when conversing with the model.

The new model significantly reduces refusals. OpenAI said the previous model would often refuse to answer questions, even when they did not violate any guardrails. Sometimes, the prior model answers “in ways that feel overly cautious or preachy, particularly around sensitive topics.”

The company promises that GPT-5.3 will not do the same and will tone down “overly defensive or moralizing preambles.” This means the model will answer directly, without caveats, so users do not end conversations without a response to their query. 

Despite this, GPT-5.3 Instant still faces some limitations, especially in some languages like Korean and Japanese, where the answers still sound stilted. 

Safety card shows regressions in sexual content and self-harm categories

The new model does not have support for adult content, according to an OpenAI spokesperson in an email to VentureBeat, as the company is still figuring out “how to maximize user freedom while maintaining our high safety bar.” OpenAI does not have a timeline for when it will release that functionality.

OpenAI conducted safety benchmarking on the new model, noting on its safety card that, while it performed well against disallowed content, it still did not match the level of GPT-5.2 Instant. However, OpenAI noted these results could change after launch.

“GPT-5.3 Instant shows regressions relative to GPT-5.2 Instant and GPT-5.1 Instant for disallowed sexual content, and relative to GPT-5.2 Instant for self-harm on both standard and dynamic evaluations,” the company said.

In other categories, OpenAI said the model performs on par with or better than previous releases, and noted the regressions for graphic violence and violent illicit behavior have low statistical significance.

Expect a new model soon?

After announcing GPT-5.3 Instant and noting that updates for Thinking and Pro will be coming soon, OpenAI teased that even this new model could be retiring.

In a post on X, OpenAI said GPT-5.4 is coming “sooner than you think.”

OpenAI did not elaborate on what changes, if any, we can expect with GPT-5.4 and which modes will get it first. 

GPT-5.2 Instant, the predecessor model, will remain available on the ChatGPT model picker until June 3, when it will be retired.