Grok 4.20 is xAI's newest flagship model released in February 2026, introducing a native 4-agent multi-agent architecture where specialized AI agents collaborate simultaneously on complex queries. It maintains a 2M-token context window — the largest among Western frontier models — and achieves a 65% reduction in hallucination rates through cross-agent verification. The model updates its capabilities weekly based on real-world usage and delivers fast direct answers at 232 tokens per second with 0.54-second time-to-first-token.