On August 21, DeepSeek officially released DeepSeek-V3.1. This generation introduces major upgrades in hybrid reasoning (thinking/non-thinking modes), efficiency, and Agent toolchain capabilities. The update is already live in the official App and web client (with a new "Deep Thinking" toggle). For API usage, deepseek-chat corresponds to non-thinking mode, while deepseek-reasoner is the thinking mode, both now supporting a 128K context window. In addition, strict Function Calling (Beta) and Anthropic API compatibility are introduced, making it easier to integrate with ecosystems such as Claude Code.