Grok 4.6 is SpaceXAI's new frontier model, and the pitch is simple: match the best models on the market while charging significantly less. It ships today across the xAI API, Cursor, Grok Build, OpenRouter, Vercel, and Cloudflare, with double the included usage in Cursor and Grok Build for the first week.

Same weights, sharper training

Grok 4.6 runs on the same 1.5 trillion parameter V9 foundation as Grok 4.5. Rather than scale the base model, SpaceXAI reworked the post-training stack, with upgraded supervised fine-tuning and reinforcement learning aimed at coding, reasoning, and instruction following. The company positions the release as a rival to current top-tier models from Anthropic and OpenAI, framed less as a raw intelligence bump and more as a model built to stick with long, multi-step jobs.

Concretely, xAI used Grok 4.5 to regenerate training trajectories across different reasoning efforts, agent setups, and domains including STEM, software engineering, and general knowledge work, then filtered out low-quality examples with automated checks. On the RL side, training spanned agentic tasks from general coding to kernel optimization, web development, and CAD work.

One notable behavioral change: the model now self-checks its outputs during longer tasks rather than producing a single pass and stopping. A new xhigh reasoning effort level sits above the existing low, medium, and high settings, useful for squeezing out extra performance on the hardest tasks at the cost of more compute.