# Inside Solar-Open2-250B: What Upstage's Own Chat Template Reveals

**Solar-Open2-250B's chat template reveals its own system prompt, reasoning controls, and self-reported scores, published by Upstage.**

## What the chat template shows

Solar-Open2-250B is a text-generation model that Upstage published on [Hugging Face](https://huggingface.co/upstage/Solar-Open2-250B) under the repository name Solar-Open2-250B. The page does not describe the model in ordinary prose; instead, the most revealing part of the listing is the model's own chat template, a Jinja file that controls how conversations are assembled before they reach the model. Buried inside it is the system prompt Upstage bakes in by default: "You are Solar Open2 250B, a large language model trained by Upstage AI, a Korean startup," with a stated knowledge cutoff of 2026-02.

## Reasoning effort and tool calls, built into the format

The template exposes a reasoning_effort setting, defaulting to "high," with levels such as medium, high, and xhigh available to a caller. A separate think_render_option controls whether the model's internal reasoning is shown "interleaved" between turns or fully "preserved," which is the kind of detail normally hidden from a model card's marketing copy. The same template also defines a strict tool-calling format, with dedicated start and end tokens for tool calls and tool responses, and a rule that any reasoning must strictly precede the call.

## Self-reported benchmark scores

Because the page doesn't include an independent write-up, the only performance numbers come from the model's own metadata, which lists three self-reported evaluation results: 86.3 on GPQA Diamond, 86.2 on MMLU-Pro, and 16.6 on Apex Agents. These are vendor-reported figures published by Upstage itself rather than an independent third-party evaluation, so they should be read as a starting point for comparison, not a settled result.

## Adoption so far

As of the page's capture, the repository had logged 2784 downloads and 573 likes on Hugging Face, and the model was last modified on 2026-07-24 after being created on 2026-07-22. The excerpt reviewed here does not spell out the model's license terms, so anyone planning to reuse the weights should check Upstage's own license page directly rather than assume a standard permissive license applies.

## Key facts

- Model: Solar-Open2-250B, a text-generation model published by Upstage on Hugging Face.
- The built-in system prompt describes it as trained by Upstage AI, a Korean startup, with a knowledge cutoff of 2026-02.
- Self-reported scores: 86.3 on GPQA Diamond, 86.2 on MMLU-Pro, 16.6 on Apex Agents.
- The chat template supports selectable reasoning-effort levels (medium, high, xhigh) and a dedicated tool-call format.
- 2784 downloads and 573 likes recorded on the Hugging Face page as of the capture date; the excerpt reviewed does not spell out the license terms.

## Check your understanding

- What does Solar-Open2-250B's own chat template reveal about how it was trained and what its knowledge cutoff is?
- Why should the 86.3 GPQA Diamond and 86.2 MMLU-Pro scores be treated as self-reported rather than independently verified?
- What is the difference between the "interleaved" and "preserved" think-rendering options in the chat template?

## Sources

- [upstage/Solar-Open2-250B on Hugging Face](https://huggingface.co/upstage/Solar-Open2-250B)

---

- Category: learn (release)
- Affects: —
- Published: 2026-07-26T07:31:57.559Z
- Original: https://huggingface.co/upstage/Solar-Open2-250B
- Generated by tinker news