What is GPT-5.3 Instant: Lesser refusals and fewer hallucinations

ChatGPT parent OpenAI launched its latest model GPT-5.3 Instant on Tuesday. OpenAI says its predecessor GPT-5.2 Instant is the company's most-used large language model (LLM) so far.


“GPT‑5.3 Instant delivers more accurate answers, richer and better-contextualised results when searching the web, and reduces unnecessary dead ends, caveats, and overly declarative phrasing that can interrupt the flow of conversation,” the company wrote in a blog post.



Based on the feedback received from users, the latest model aims to make the conversation more contextual but less wordy, and also improve the tone and relevance.


In contrast to the more cautious GPT-5.2 Instant which refused seemingly insensitive prompts, GPT-5.3 Instant gives more direct answers by reducing unnecessary refusals and cutting ‘overly defensive or moralising preambles’, resulting in fewer dead ends and more useful responses.


For context, GPT-5.2 Instant was launched in December 2025, at a time when sexually explicit content was on the rise and was drawing significant public attention, prompting renewed scrutiny of institutional oversight.


“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,” OpenAI added.


This means it will deliver ‘immediately usable’ information instead of summarising online data without putting active reasoning into the answer.


GPT‑5.3 Instant also claims to reduce hallucination rates by 26.8% when using the web and 19.7% when relying only on its internal knowledge, compared to GPT-5.2. Hallucination rate is the percentage of time an LLM produces incorrect or fabricated information as fact. A lower rate means fewer hallucinations.


The updated model is available to all users including free and paid users. “Updates to Thinking and Pro will follow soon. GPT‑5.2 Instant will remain available for three months for paid users in the model picker under the Legacy Models section, after which it will be retired on June 3, 2026,” the company added.