OpenAI claims ChatGPT’s new default model hallucinates way less

The Verge / 5/6/2026

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Key Points

  • OpenAI says ChatGPT’s newest default model, GPT-5.5 Instant, delivers “significant improvements in factuality” compared with its prior Instant model.
  • The company reports that internal evaluations show GPT-5.5 Instant generated 52.5% fewer hallucinated claims on high-stakes prompts in areas such as medicine, law, and finance.
  • OpenAI also claims a 37.3% reduction in inaccurate claims on especially challenging conversations that users had previously flagged for factual errors.
  • The announcement is positioned as a response to the broader, ongoing issue of AI hallucinations in chat systems.

OpenAI's newest default model for ChatGPT might not make stuff up as much. Hallucinations have been an ongoing problem for AI models, but OpenAI says its new GPT-5.5 Instant model has "significant improvements in factuality across the board."

The company claims that, based on "internal evaluations," GPT-5.5 Instant produced "52.5% fewer hallucinated claims" than its Instant model for GPT-5.3 "on high-stakes prompts covering areas like medicine, law, and finance." GPT-5.5 Instant also "reduced inaccurate claims by 37.3% on especially challenging conversations users had flagged for factual errors." (OpenAI has some information about how it ev …

Read the full story at The Verge.