Grok 4.20 Beta Reasoning is xAI's reasoning model in the Grok 4.20 beta generation, supporting extended thinking for complex problem-solving with low hallucination rates and strict prompt adherence.
import { streamText } from 'ai'
const result = streamText({ model: 'xai/grok-4.20-reasoning-beta', prompt: 'Why is the sky blue?'})Grok 4.20 Beta Reasoning was released March 11, 2026 as the beta-tagged variant of xAI's Grok 4.20 reasoning model. It generates visible chain-of-thought reasoning before producing its final answer, letting it work through multi-step problems, mathematical proofs, and complex code analysis more reliably than direct-response models.
The reasoning architecture adds latency per request but improves accuracy on tasks that benefit from deliberation: debugging intricate code paths, synthesizing information across long documents, and solving problems that require intermediate steps. Combined with the Grok 4.20 generation's low hallucination rates, this makes Grok 4.20 Beta Reasoning suitable for high-stakes analysis where correctness matters more than speed.
As a beta release, Grok 4.20 Beta Reasoning may receive weight or behavior updates. For stable reasoning workloads, use the non-beta grok-4.20-reasoning.