OpenAI ships GPT-5.6 as three tiers with in-model tool calling
OpenAI moved GPT-5.6 to general availability on July 9, 2026, launching Sol, Terra, and Luna at $5/$30, $2.50/$15, and $1/$6 per 1M input/output tokens respectively.
Sol scores 80 on Artificial Analysis Coding Agent Index (2.8 points above Claude Fable 5) and reaches 62.6% on OSWorld 2.0 using 85% fewer output tokens than Opus 4.8.
Programmatic Tool Calling executes model-written JavaScript in an isolated V8 runtime, cutting prompt tokens by 38% (Clio) and total tokens by 63.5% (PlayCo) by eliminating intermediate round-trips.