Model field manual / Updated July 10, 2026

GPT-5.6 Sol, Terra, and Luna explained.

Three tiers, three jobs. Sol handles the hardest judgment. Terra is the everyday default. Luna is built for fast, inexpensive volume.

Choose your tierOpen cost calculator
LevelComplete beginner
Time8 minutes
OutputYour model routing rule
Source dateJuly 10, 2026

The plain-English answer.

Do not treat the tiers like a ranking where the biggest model must do everything. Treat them like a small team. The expensive tier should handle the few decisions that deserve it.

Flagship

Sol

Use Sol for strategy, hard architecture, difficult debugging, sensitive editing, and final review when mistakes are expensive.

Everyday default

Terra

Use Terra for most business work, coding, research synthesis, first drafts, and routine problem solving.

Fast volume

Luna

Use Luna for extraction, tagging, rewriting, summaries, simple support, and batch work with clear checks.

Choose by consequence, not hype.

Ask what happens if the answer is wrong. That single question is more useful than chasing benchmark charts.

TaskStart withMove up whenMove down when
Business strategyTerraThe decision is costly, public, or hard to reverseThe output is a structured checklist
Software workTerraArchitecture or debugging needs deeper judgmentThe task is mechanical and tests are strong
ContentTerraVoice, positioning, or final editorial quality mattersYou need bulk variants from an approved source
Data processingLunaEdge cases require reasoningStay on Luna when rules and checks are clear
Final approvalSolAlready at the right tierThe work is low risk and easy to verify

StackPilot routing rule

Plan high. Work balanced. Process cheap.

1. Plan

Use Sol for the small number of difficult choices that shape the whole project.

2. Work

Use Terra for the main draft, build, or analysis loop.

3. Process

Use Luna for repeatable substeps with explicit formats and verification.

Three common mistakes.

The model name matters less than the job definition, source quality, and review loop.

Sol for everything

You pay frontier prices for routine work that a smaller model could handle.

Luna with vague instructions

Cheap models need tighter scope, clearer examples, and better checks.

No verification

A stronger model is not permission to skip source checks or human review.

Source desk

Verify before you buy or publish.

This guide was prepared from OpenAI's July 9, 2026 GPT-5.6 release information and cross-checked against the active GPT-5.6 model available in Hermes. Product names, access, and prices can change.

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