OpenAI: GPT-6 Luna Decisions vs Upstage: Solar Decide
A side-by-side comparison of OpenAI: GPT-6 Luna Decisions ($0.35 / 1M tokens) and Upstage: Solar Decide ($0.18 / 1M tokens) using current USD prices and capabilities from the api14 catalog. Both run through the same OpenAI-compatible API.
Specifications
| OpenAI: GPT-6 Luna Decisions | Upstage: Solar Decide | |
|---|---|---|
| Provider | OpenAI | Upstage |
| Input | $0.35 / 1M tokens | $0.18 / 1M tokens |
| Web search | $35.00 / 1K searches | - |
| Cache read | - | $0.18 / 1M tokens |
| Context window | 1,050,000 | 524,288 |
| Max output | 945,000 | 471,859 |
| Input | text, image | text |
| Output | decisions | decisions |
| Tool calling | ||
| Structured output | ||
| Reasoning control | ||
| Added | Oct 6, 2026 | Sep 28, 2026 |
Key differences
- Upstage: Solar Decide is 50% cheaper on input tokens.
- OpenAI: GPT-6 Luna Decisions reads 2.0× more context (1,050,000 tokens).
- A request with 1,000 input and 500 output tokens costs $0.000350 with OpenAI: GPT-6 Luna Decisions and $0.000175 with Upstage: Solar Decide.
In depth
OpenAI: GPT-6 Luna Decisions is a decisions model from OpenAI, listed under the model id openai/gpt-6-luna-decisions. Upstage: Solar Decide is a decisions model from Upstage, listed as upstage/solar-decide. Both sit in the same category, so neither is a general chat model or a code model by label. They are built to return decisions as their output modality, which means you should expect a choice, a verdict or a classification rather than free form prose. The provider release dates are close together, with Solar Decide listed on 2026-09-28 and GPT-6 Luna Decisions on 2026-10-06.
The clearest split is context and input. GPT-6 Luna Decisions accepts text and image input and carries a context window of 1,050,000 tokens. Solar Decide accepts text only and carries 524,288 tokens, so the OpenAI model has the bigger context by roughly a factor of two and is the only one of the two that can look at images. Both output decisions, and the comparison data records no difference in tool use, structured output or reasoning support, so treat those as not meaningfully different here rather than as advantages for either side. On price, Solar Decide is the cheaper input option, while output pricing is about the same or not meaningfully different.
For practical work, reach for GPT-6 Luna Decisions when the decision depends on a large body of material, such as a long contract, a full repository of documents or a lengthy thread you want judged in one pass, and when part of the evidence is a screenshot, a scanned form or a diagram. Reach for Solar Decide when the input is text, the context fits comfortably inside its window, and input cost matters to you, since it is the cheaper input side. If your task is a short text classification or a routing decision over a few thousand tokens, Solar Decide covers it, and paying for the larger window buys you nothing.
Calling either model through api14 works the same way, because the API is OpenAI compatible. You point your existing client at api14, send a request in the usual chat completions shape, and set the model field to the id you want. Switching between them is a one line change: use openai/gpt-6-luna-decisions for the OpenAI model, or upstage/solar-decide for the Upstage model. Nothing else in your request has to change, and since neither model lists supported parameters, keep your payload simple and avoid assuming tuning knobs that are not offered.
There is a case where Solar Decide is still the better pick even though the OpenAI model is larger. If your inputs are text only, your context fits within 524,288 tokens, and input spend is a concern, the cheaper input side wins on cost without costing you capability you would actually use. The reverse also holds: if images are part of the input, Solar Decide cannot take them, so GPT-6 Luna Decisions is the only option between the two.
Switch with one string
Both models use the same endpoint and request shape. Change the model value from "openai/gpt-6-luna-decisions" to "upstage/solar-decide" and prompts, streaming and tools keep working.
import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://api14.com/api/v1",
apiKey: process.env.API14_API_KEY,
});
const result = await client.post("/decisions", { body: {
"model": "upstage/solar-decide",
"state": "Customer: I was charged twice for my order and want my money back.",
"questions": {
"team": {
"type": "choice",
"instructions": "Which team should handle this message?",
"criteria": {
"billing": "Payments, refunds, invoices",
"support": "Product questions and bugs",
"sales": "Pricing and new purchases"
}
},
"urgent": {
"type": "noul",
"instructions": "Does this need a reply today?",
"criteria": {
"true": "Money, outage or legal risk",
"false": "Can wait"
}
}
}
} });
console.log(result.answers);
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