GPT-5.6 Sol vs. Terra vs. Luna vs. Cyber: A Tier Selection Guide

By Carlos Montiel | Enterprise AI Specialist
Leer en español →
Published: 2026-07-28 | By: Carlos Montiel | Reading time: ~4 minutes

Four names for four different jobs. Picking the wrong tier doesn't just cost more than necessary — for long-context work, it can directly return the wrong answer.

The three public tiers, priced and purposed

Sol is the flagship for hard coding, agents, and research — $5/$30 per million tokens. Terra is the balanced option, with quality close to GPT-5.5 at less than half the price — $2/$12 since the July 30, 2026 price cut. Luna is the cheapest, optimized for latency — $0.20/$1.20 after an 80% price cut.

Where Sol really pulls ahead

Sol scores 61 points at maximum effort on the independent Artificial Analysis index, and leads the Coding Agent Index with 80 points — for complex coding and agentic tasks, the gap versus Terra and Luna isn't marginal, it's substantial.

The long-context trap with Luna

Sol and Terra land nearly tied on long-context tasks (91.5% and 89.6% respectively), while Luna drops to 41.3% — a significant performance cliff for document analysis and multi-document synthesis. If your workload involves long-context retrieval (document analysis, reasoning over large codebases, multi-document synthesis), Luna is the wrong tool, no matter how much cheaper it is per token.

The default recommendation

Terra is the sensible default for most work. Sol for the hardest agentic tasks. Luna for high-volume pipelines — but only once you've confirmed the task doesn't depend on long context, given the performance cliff documented above.

GPT-5.6-Cyber: the tier you can't simply sign up for

GPT-5.6-Cyber is a model trained specifically for cybersecurity, built on top of Sol, available only through OpenAI's Daybreak Red trusted-access program — no public API and no published price. We already covered the Daybreak program in detail: this tier isn't a standard catalog option, it's restricted, vetted access for legitimate offensive and defensive security use cases.

Carlos Montiel
Enterprise AI Solutions Architect
Specialist in LLMs, Agents, and Orchestration
guatemalia.com/en/#contact · info@guatemalia.com

Need to implement AI at your company?

Carlos Montiel is an enterprise AI solutions architect. He implements LLMs, Agents, RAG, and orchestrators for companies across Guatemala and Latin America. Reach out for a consultation.

Contact Carlos Montiel

info@guatemalia.com