Dreaming V3 Explained: Build Sleep-Time Memory in Python

On June 4, OpenAI shipped Dreaming V3, the biggest overhaul of ChatGPT memory since the feature first appeared in 2024. Instead of waiting for you to say “remember this,” a background process now runs after your conversations end, quietly synthesizing what mattered: your preferences, active projects, and time-sensitive context. It even rewrites memories as the world changes. OpenAI's own example: “the user is going to Singapore in July” becomes “the user went to Singapore in July 2026” once the trip is over, so the assistant stops recommending Singapore restaurants in August.

The feature is consumer-only. There is no Dreaming API endpoint you can call. But the architecture behind it, often called sleep-time compute, is something you can absolutely build for your own agents today, and it fixes the single most annoying property of LLM apps: they either forget everything or remember everything forever, including stale junk.