Elon Musk announced on July 9 that xAI’s Grok is getting a 1M+ token context window, a feature designed to close the gap with Anthropic’s Claude Opus, which hit that milestone months earlier. Anthropic’s Claude Opus 4.6 reached 1M tokens by late March 2026 and scored 78.3% on the MRCR v2 benchmark for 1M-context retrieval, which led all AI models at that time. Grok’s standard models previously topped out at 256K tokens, though some fast variants reportedly reached 2M tokens with trade-offs in other capabilities. The forthcoming Grok 4.5 release appears aimed at making the 1M+ window a standard feature rather than an edge-case variant. Musk founded xAI in 2023 with the explicit goal of building AI that could compete with, and eventually surpass, the models coming out of OpenAI and Anthropic.