This week in OpenAI

OpenAI adjusts ChatGPT model behavior and cuts GPT‑5.6 API prices

ChatGPT churn: model defaults and behavior changed across tiers in the same week
API economics: GPT‑5.6 Luna price dropped by 80% according to OpenAI Devs
Controls focus: OpenAI framed tier expansion as subject to abuse guardrails

OpenAI shipped a ChatGPT update for GPT‑5.6 Sol and expanded access to GPT‑5.6 Luna across lower tiers. Separately, OpenAI announced large API price reductions for GPT‑5.6 Luna and smaller cuts for Terra, alongside a new Fast mode option for Sol.

OpenAI updates GPT‑5.6 Sol and expands Luna access

OpenAI said it updated GPT‑5.6 Sol in ChatGPT to be more reliable with facts and more focused in answers for Plus and Pro users. OpenAI also said GPT‑5.6 Luna will become the default for Free and Go users this week, with unlimited text chats, and it will add a Think button for harder questions next week subject to abuse guardrails.

Expect user-facing output changes without tenant-side configuration, which affects internal guidance, examples, and support scripts for ChatGPT users.
Treat Free-tier expansion as a driver of shadow usage and pre-procurement experimentation, and align your usage policy and DLP posture accordingly.
Use the stated guardrail framing as a vendor-evaluation input for predictability and risk controls when comparing assistants for regulated workflows.

Source — OpenAI (Product update) ChatGPTModels