Grok is xAI's LLM family: founded July 2023, opened with a 314B MoE under Apache 2.0 in March 2024, and two and a half years later spans Grok 4.6 (500K, $2/$6, four reasoning levels), Grok 4 Fast (2M), Imagine for image/video, and Grok Build for terminal coding — its moat is distribution (X / grok.com / Tesla / Bedrock), not single-model supremacy. This post traces Grok 1→4.6, sub-line positioning, pricing, and licensing traps.
Grok Build is xAI's Rust coding agent — 845K LOC, 8 parallel sub-agents, Arena Mode. May 2026 beta, July open-sourced (Apache 2.0) — but the direct trigger for open-sourcing was a privacy incident: it silently uploaded entire repos (including SSH keys, .env files) to Google Cloud Storage at a 27,800x traffic ratio. The exfiltration code remains in the binary, disabled only by a server-side flag.
Grok 4.6: 500K-token context window, $2 input / $6 output per 1M tokens (same as 4.5), AA Intelligence Index 61 (tied with GPT-5.6 Sol Max), GDPVal-AA v2 1753 Elo (highest overall), but DeepSWE and Terminal-Bench still trail GPT-5.6 Sol and Claude Fable 5