Best OpenAI flagship — leads terminal coding and agentic browsing.
Frontier agentic coding, deep research, and hardest reasoning tasks
Repo-level coding is the main job — Opus 5 leads SWE-bench Pro by ~15 points — or you're cost-sensitive (Terra is 60% cheaper at 1–4 points off).
First frontier model family to clear a customer-by-customer US government review: limited preview June 26, full public release July 9, 2026. Pricing $5/$30 ($10/$45 above 272K context). Knowledge cutoff Feb 16, 2026.
Terminal-Bench 2.1 leader at 88.8% (91.9% ultra) — the top OpenAI agentic-coding result
94.6% GPQA Diamond and 90.4% BrowseComp — frontier science reasoning and agentic browsing
Artificial Analysis Coding Agent Index leader at 80 points, near Fable 5 intelligence at roughly one-third the cost
Trails Claude Opus 5 badly on repository-level engineering (SWE-bench Pro 64.6% vs 79.2%)
Long-context surcharge ($10/$45 above 272K) and 2–3x ultra-mode costs stack up fast
What people actually use GPT-5.6 Sol for.
Tool-heavy terminal coding — 88.8% on Terminal-Bench 2.1 (91.9% in ultra mode, a state of the art)
Agentic web research at 90.4% BrowseComp with top-tier GPQA Diamond science reasoning (94.6%)
Long autonomous workflows using ultra mode's sub-agent orchestration
Frontier agentic coding, deep research, and hardest reasoning tasks. Start free — no card required.
Recommendations are made independently based on real-world use and public benchmarks. See our disclosures for details.
Pricing moves, ranking shifts, and capability updates.
The GPT-5.6 family (Sol, Terra, Luna) reached full public release on July 9, 2026 after becoming the first frontier models to clear a customer-by-customer US government review. On July 30, OpenAI cut prices: Terra from $2.50/$15 to $2/$12 (~20% off), and Luna from $1/$6 to $0.20/$1.20 (~80% off). Sol stays at $5/$30. All three now have full model pages in our ranked catalog.
View modelGPT-5.6 Sol is best for frontier agentic coding, deep research, and hardest reasoning tasks. It is a strong fit when that workflow matters more than the tradeoffs around premium pricing and deliberate speed.
Repo-level coding is the main job — Opus 5 leads SWE-bench Pro by ~15 points — or you're cost-sensitive (Terra is 60% cheaper at 1–4 points off).
Mistral: Mistral Nemo is the lower-cost option to compare first when you want a similar workflow fit with less token spend.
GPT-5.6 Sol is the better pick when response time matters more than maximum depth or premium quality.
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