OpenAI

GPT-5.6 Sol

OpenAI's most capable model — the top tier of the GPT-5.6 family, built for frontier coding, cybersecurity, and enterprise knowledge work.

Context window

1.05M tokens

Input / M tokens

$5.00

Output / M tokens

$30.00

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GPT-5.6 Sol is the top tier of OpenAI’s three-model GPT-5.6 lineup (Luna, Terra, Sol), positioned as the strongest option for coding, enterprise work, and cybersecurity tasks, with a claim on efficiency alongside raw capability.

Why it stands out

Largest context window on this list at roughly 1.05M tokens, useful for whole-repo or multi-document coding sessions.
Tiered family — Sol is the top of Luna/Terra/Sol, so you can drop to a cheaper sibling for lighter workloads without leaving the ecosystem.
Broad tool ecosystem, including deep integration with the wider OpenAI API and agent tooling.

Good for

Teams already built on the OpenAI stack who want the top tier of that stack for their hardest coding and agentic tasks.