Grok 4.20 Beta Reasoning (0309) (xAI)

Grok 4.20 Beta Reasoning (0309) is catalogued within the Grok family as a closed-weight variant from xAI that prioritizes explicit chain-of-thought reasoning, tool calling, structured output, and configurable temperature behavior for downstream applications. Aggregator metadata describes it as accepting text and image inputs while returning text only, positioning it for workloads where a vision-aware front end feeds into a text-generation reasoning step. The variant label "Beta" and the dated 0309 suffix indicate an experimental snapshot within the broader 4.20 series rather than a generally stable release.

Practically, the variant is aimed at use cases that benefit from a reasoning pass followed by tool-augmented actions, such as multi-step analysis, code or agent workflows, and retrieval-heavy question answering where attachment ingestion is useful. It sits alongside sibling 4.20 entries such as the non-reasoning counterpart and the multi-agent configuration, giving integrators a way to choose between lighter and heavier reasoning behavior within the same generation. Because no creator-published model card, technical report, or benchmark numbers were provided in the supplied evidence, any claim about training scale, architecture, parameter count, or relative performance against peers is unsupported and should be treated as unverified.