The new GPT-5.6 family: Luna, Terra, Sol
Why CEREBRO kept it
GPT-5.6 family launch details; direct coding-agent model release.
The text below is an automated extraction of the article at https://simonwillison.net/2026/Jul/9/gpt-5-6/#atom-everything, stored verbatim in the public cerebro-vault repository. Copyright remains with the original publisher (simonwillison.net).
<p>OpenAI's latest flagship model <a href="https://openai.com/index/gpt-5-6/">hit general availability this morning</a>, and comes in three sizes: Luna, Terra, and Sol (from smallest to largest).</p> <p>The new models are priced per 1M input/output tokens as Luna $1/$6, Terra $2.50/$15, Sol $5/$30. For comparison, the Claude Opus series are $5/$25 and the Claude Fable 5 is $10/$50, but price-per-million tokens doesn't tell us much now that the number of reasoning tokens can differ so much between models for the same task.</p>
<p>All three models have a February 16th 2026 knowledge cutoff, a m
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