OpenAI in practice

GPT-5.6 Sol, Terra and Luna: choose the right model

Sol rather than “Soul”: understand the documented GPT-5.6 models and compare quality, response time and rework for business processes.

WERKVERSTAND / CONNECTING INTELLIGENCE

The essential answer

The official name is GPT-5.6 Sol. OpenAI also documents Terra and Luna as variants with different capability and cost positioning. For a business, the best choice is the model that reliably meets the specific assignment. Keep model names, ChatGPT subscriptions and API operations separate.

01 / FIT

A good fit when

  • Recurring tasks with assessable quality and rework.

02 / LIMITS

Not the first choice when

  • No universal business ranking and no claimed “Soul” product announcement.

Which names are documented?

OpenAI describes Sol as a model for complex professional work; the API alias gpt-5.6 points to Sol. Terra is positioned as a balance of capability and cost, while Luna targets cost-sensitive, high-volume work. An OpenAI model named “Soul” could not be confirmed in the official sources checked.

Separate tasks by decision complexity

Clear categories and good examples are particularly important for basic inbox classification. Proposal assessment instead needs to account for conflicting requirements, exceptions and the consequences of a wrong assignment. These tasks need different quality criteria even when they use the same documents.

Our recommendation is to separate routine preparation from consequential decisions. One model can structure the input; borderline cases move to a more demanding check or the responsible person. Validate escalation using rules and sample review, rather than the confidence of the answer.

A selection test for sales

Build a small set of anonymized inquiries: a complete request, one with a conflicting budget, one without a clear owner and one outside your offering. Ask each model to extract the same fields and propose a next action. Sales independently assesses whether that action is correct and actually executable.

  • Complete required fields or explicitly mark them unknown.
  • Do not invent commitments on price, timing or scope.
  • Measure incorrect routing and manual corrections as separate costs.

Total cost rather than token price

The official selection method prioritizes quality, followed by cost and speed. Business costs also include integration, retries, monitoring and rework. Compare cost per accepted result: a result counts only after it meets the requirements defined beforehand.

Check current provider prices and plan limits when making the purchasing decision. API prices do not describe a ChatGPT subscription. A visible model name on one surface also does not establish that the same tools are enabled on another.

Start with an evidence-based default

For each workflow, record the default model, permitted data, acceptance criteria and escalation route. Start by collecting the few errors that genuinely interrupt work and improve the process around them. Frequent model changes make comparison difficult when prompts and sources change at the same time.

The AI System Check helps identify the right task category. A subsequent audit turns it into a bounded pilot with a measurable decision instead of a universal model ranking.

Keep it verifiable

Primary sources

The next sensible step

Find the right AI workflow

Eight steps from a general interest in AI to a clearer decision for your business.

Start AI System Check
FreeProvider-neutralNo credentials