OpenAI Releases GPT-5.6 (Sol, Terra, Luna): A Three-Tier Model Family With Programmatic Tool Calling in the Responses API
OpenAI shipped a three-tier model family with a substantive architectural shift (Programmatic Tool Calling) that fundamentally changes how agents orchestrate tools, reducing token overhead by 38-63% while competitive positioning remains contested on reasoning and software engineering tasks.
Why it ranks · · GPT-5.6 released July 9, 2026 with three tiers: Sol ($5/$30 per 1M tokens), Terra ($2.50/$15), Luna ($1/$6) · Jul 6 – 12, 2026
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