Source · release
OpenAI API changelog: GPT-6.1 Sol, Agents API computer use, ultrafast tier
Summary
OpenAI's API changelog entry for 2026-09-29 confirms the release of GPT-6.1 Sol
(gpt-6.1-sol), which OpenAI positions for complex coding and professional work at a
lower cost than GPT-6 Astra. The same day, the Agents API gained hosted computer use, and
GPT-6 Astra gained an "ultrafast" service tier. Later entries add an image-encoding fix
(2026-09-25) and HIPAA compliance setup in organisation settings (2026-10-05).
Key points
- GPT-6.1 Sol: $2 input, $0.10 cached input, $2.50 cache writes, $10 output per 1M tokens. It supports multi-agent work (beta) through the Responses API.
- Agents API computer use: agents work in an OpenAI-hosted browser; the application handles website access approvals and sign-in.
service_tier: "ultrafast"ongpt-6-astrareduces time between output tokens. It supports global processing with US data residency but no EU regional processing.- 2026-09-25: a bug in image encoding had degraded image understanding in GPT-6 Sol and Luna. OpenAI advises rerunning image evals.
- 2026-10-05: administrators can now accept a Business Associate Agreement (HIPAA) in API organisation settings.
Why it matters
This is the primary source for GPT-6.1 Sol, which earlier notes only recorded as reported. Hosted computer use in the Agents API moves browser automation from the client side to an OpenAI-run environment.