Solar Pro 4

Solar Pro 4 is Upstage's proprietary reasoning-focused agentic LLM (text→text) for finishing multi-step commercial work: long documents, terminal tasks, and multi-turn tool use. Supports English, Korean, and Japanese with a ~512K context window (OpenRouter listing ~524K) and up to 128K output tokens. Reasoning effort is adjustable (high for deep analysis, low for fast chat). Vendor/AA self-reported highlights include Terminal-Bench v2.1 57, τ³-Banking 23, AA-LCR 71, and GPQA Diamond 89.0; in-house asterisk rows include BrowseComp 49.2, SWE-Bench Verified (OpenHands) 70.6, MMLU-Pro 86.3, LiveCodeBench 87.8, AIME 2026 95.3. GDPval-AA v2 38.8 is noted here only — catalog gdpval-aa is Elo-scale (max_score 3000) and 38.8 does not fit that encoding (no gdpval-aa-v2 id). Standard list pricing is $0.30 input / $0.06 cached input / $1.20 output per 1M tokens; launch promo is 90% off on Upstage Console and OpenRouter through September 10, 2026 (23:59 UTC) — promo not stored in the provider price row. Also available via SolarChat, Hermes Agent, and Upstage Studio.