DeepSeek V3.1 Terminus is DeepSeek's September 22, 2025 refined iteration of V3.1. It delivers more stable outputs with improvements to multilingual consistency, Code Agent performance, and Search Agent capability.
import { streamText } from 'ai'
const result = streamText({ model: 'deepseek/deepseek-v3.1-terminus', prompt: 'Why is the sky blue?'})DeepSeek V3.1 Terminus was released September 22, 2025 as a refined iteration of DeepSeek-V3.1, responding directly to user feedback from V3.1's August release. Rather than introducing new architectural features, Terminus focuses on reliability. It eliminates Chinese-English language-mixing errors, removes spurious random character insertions, and delivers more consistent outputs across benchmarks.
The "Terminus" designation signals a mature, production-hardened checkpoint rather than an intermediate development release. Benchmark comparisons show DeepSeek V3.1 Terminus delivers more stable results than V3.1, with particular strength in Code Agent and Search Agent performance. Output consistency in these areas directly affects task success rates in automated pipelines. Weights are available on Hugging Face at the official DeepSeek repository.
The model launched simultaneously across DeepSeek's App, Web, and API surfaces, making it the production-recommended version of the V3.1 generation. If you're running V3.1 and experienced inconsistent multilingual outputs or agent reliability issues, Terminus is the designated upgrade path within the same generation before moving to V3.2.