DeepSeek Reasoner V3.2 is not a separate model — it is DeepSeek V3.2 running in thinking mode. The underlying architecture is identical to standard V3.2: a 685-billion-parameter Mixture of Experts (MoE) model with DeepSeek Sparse Attention (DSA). What changes is the inference behavior: in thinking mode, the model generates a full internal chain-of-thought reasoning trace — visible in the reasoning_content field of the API response — before producing its final answer.
On DeepSeek's API, this mode is accessed by calling the model ID deepseek-reasoner. The alias was previously mapped to DeepSeek R1, then upgraded through each generation — V3.1-Terminus thinking, V3.2-Exp thinking — and now points to V3.2's thinking mode. When you call deepseek-reasoner today, you are running V3.2 with extended reasoning enabled.
The key capability that distinguishes it from DeepSeek R1: Reasoner V3.2 supports tool use during thinking. It preserves its reasoning trace across tool calls within a single user turn — so when an agent calls 10 tools to answer one question, the model doesn't have to re-reason the problem from scratch after each tool result. This makes it significantly more effective for real agentic pipelines than R1.