Four high-profile AI labs released frontier language models within a three-week stretch in July 2026. xAI shipped Grok 4.5 on July 8 at $2/$6 per million tokens, undercutting Opus 4.8 pricing by over 60%. Anthropic released Claude Opus 5 on July 24 as the new default model on Claude Max subscriptions. Moonshot AI published Kimi K3, its largest model at 2.8 trillion parameters. Grok 4.5 from xAI, Claude Opus 5 from Anthropic, the GPT-5.6 family from OpenAI, and Kimi K3 from Moonshot AI each target getting an AI system to carry a multi-hour task without losing track of the plan. Grok 4.5 runs on a 1.5 trillion parameter base and was trained in part on real usage data from Cursor. Pricing sits at $2 per million input tokens and $6 per million output tokens, with a 500,000 token context window. Independent trackers place it fourth on the Artificial Analysis Intelligence Index at pricing more than 60% below Claude Opus 4.8 and GPT-5.5. On Terminal-Bench 2.1, Grok 4.5 scored 83.3%. xAI says the model needs roughly a fifth of the output tokens Opus 4.8 required. Claude Opus 5 carries the same $5