Solar Pro 4
Upstage’s model that says when it cannot verify something, rather than filling the gap.
About Solar Pro 4
Solar Pro 4 is the commercial flagship of Upstage, the Korean AI company, rebuilt for agent work. Its defining trait is restraint: Upstage designed it to say it cannot verify a claim instead of inventing one, and to answer from the evidence in long, multi-document inputs. That roughly tripled its Artificial Analysis Intelligence Index score over Solar Pro 3, to 42.
Upstage officially supports English, Korean and Japanese, and reports 89.0% on GPQA Diamond. Some of its gains come from declining to answer rather than knowing more — which is exactly what you want when the documents are contracts and reports.
Where it’s strong
Questions over contracts, reports and other long documents.
Banking and customer-service agents that must not guess.
Korean and Japanese business documents.
Where to be careful
Slow on agent tasks: about 8.6 minutes per task in one independent test.
Independent testing found a usable context of about 384K tokens, short of the 512K Upstage states.
Well below the frontier models in absolute terms.
Price
For scale: 1,000 requests of about 3,000 tokens in and 1,000 out cost $0.82 — a long prompt and a page of answer each. Every rate is published and stays the same from one request to the next. See every model.
Specs
solar-pro4Call it
Use the OpenAI SDK you already have — point it at Roar AI and name the model. Read the docs.
from openai import OpenAI
client = OpenAI(base_url="https://api.roar-ai.com/v1", api_key="roar_live_…")
reply = client.chat.completions.create(
model="solar-pro4",
messages=[{"role": "user", "content": "Summarise this contract in plain English."}],
)Compare Solar Pro 4
Questions
How much does Solar Pro 4 cost?
Input is $0.117 per 1M tokens; output is $0.468 per 1M tokens. For scale, 1,000 requests of about 3,000 tokens in and 1,000 out cost $0.82. The rate is published and does not change from one request to the next.
Can I use Solar Pro 4 alongside other models?
Yes. Every model on Roar AI is on the same API key and the same monthly invoice, so switching from Solar Pro 4 to another model is a change to one word in your code.
Is Solar Pro 4 open source?
No. Upstage does not publish the weights, so it is only available through an API like this one.