DeepSeek V3.1 Terminus

by DeepSeek

DeepSeek-V3.1 Terminus, released in September 2025, refines V3.1 with targeted production-stability improvements. The 671-billion-parameter model keeps 37 billion active parameters and a 128K-token context while addressing the language-consistency and tool-use issues users reported. The update reduces Chinese-English code-mixing and stray-character generation seen in earlier versions, producing more reliable multilingual output. DeepSeek also reports stronger Code Agent and Search Agent behavior, making Terminus a steadier choice for multi-tool agentic workflows. It retains the hybrid thinking and non-thinking modes of V3.1 and is available with open weights on Hugging Face, aimed at deployments that need robust, predictable multilingual performance.

Key info

Input
Output
Features
Context window
164K
Max output
164K

Benchmarks

Independent benchmark scores — composite indices for reasoning, coding, and math, plus individual eval scores where available.

Intelligence Index13.9
Math Index53.7
Reasoning & knowledge
MMLU-Pro
84%
GPQA Diamond
75%
Humanity's Last Exam
9%
Long-context reasoning
45%
Coding
LiveCodeBench
53%
Agentic & tool use
Terminal-Bench Hard
32%
τ²-Bench Telecom
37%
Math & instruction following
AIME 2025
54%
IFBench
41%

Available routes

No routes currently available — DeepSeek V3.1 Terminus isn't routed through the Opper gateway right now. It may return.

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