GPT-5.5 Instant: smarter, clearer, and more personalized

Source: OpenAI Blog

Key Improvements

• Stronger, tighter answers across subject areas
• More natural conversational tone
• Better use of context you’ve already shared when personalization can help

Factuality

Instant is now more dependable, with significant improvements in factuality across the board and the largest gains in domains where accuracy matters most. In internal evaluations:

• 52.5% fewer hallucinated claims than GPT‑5.3 Instant on high‑stakes prompts (medicine, law, finance)
• 37.3% reduction in inaccurate claims on challenging conversations flagged for factual errors

Everyday Tasks

GPT‑5.5 Instant is a generally smarter model that’s more capable across everyday tasks, including:

• Improved analysis of photo and image uploads
• Better performance on STEM‑related questions
• Smarter decisions about when to use web search for more useful answers

These improvements are reflected in gains on evaluations across visual reasoning, math, and science.

Response Quality

• Tighter, more to‑the‑point answers without losing substance
• Reduced verbosity and over‑formatting
• Fewer unnecessary follow‑up questions and gratuitous emojis

Enhanced Personalization

Instant now uses context from past chats, files, and Gmail (if connected) more effectively, so answers feel more personally relevant while keeping you in control. It:

• Decides intelligently when additional personalization can improve a response
• Searches past conversations faster, reducing the need to repeat information
• Helps with tailored suggestions, plans, and picking up where you left off

Memory Sources

We’re introducing memory sources across all ChatGPT models, giving you visibility over what context was used to personalize responses:

• When a response is personalized, you can see the sources (saved memories, past chats) and delete or correct outdated items.
• Memory sources are private; they aren’t shown to others if you share a chat.
• You can manage memory through settings: delete chats, edit saved memories, or use temporary chats that don’t update memory.

Note: Memory sources may not display every factor that shaped an answer; they show the most relevant past chats rather than the full search history. We’ll continue improving this view over time.

Rollout Details

• GPT‑5.5 Instant is rolling out today to all ChatGPT users, replacing GPT‑5.3 Instant as the default model, and in the API as chat-latest.
• For paid users, GPT‑5.3 Instant will remain available for three months via model configuration settings before retirement.
• Enhanced personalization from past chats, files, and connected Gmail is rolling out to Plus and Pro users on the web and will arrive soon on mobile, with plans to expand to Free, Go, Business, and Enterprise in the coming weeks.
• Memory sources are rolling out across all ChatGPT consumer plans on the web and soon on mobile. Availability of specific personalization sources may vary by region.