SpaceXAI releases Grok 4.5

SpaceXAI — xAI’s operations under SpaceX, following the companies’ merger earlier in 2026 — released Grok 4.5, its first model built jointly with the coding startup Cursor. The partnership followed SpaceX’s agreement, announced weeks earlier, to acquire Cursor for $60 billion in stock, one of the largest acquisitions of a venture-backed startup on record. Grok 4.5 was trained on a 1.5-trillion-parameter foundation using data from Cursor coding sessions, and xAI targeted it beyond software engineering at agentic knowledge work, including legal and financial tasks.

Elon Musk described the model as roughly comparable in capability to Anthropic’s Claude Opus 4.8 while being faster and cheaper to run; xAI reported 83.3% on the Terminal-Bench 2.1 coding benchmark. Independent confirmation of the company’s benchmark figures was not available at launch, and reporting on the published numbers described a mixed picture against Opus 4.8 on other tasks. Pricing was set at $2 per million input tokens and $6 per million output tokens, undercutting rival frontier coding models. The model was not available in the EU at launch.

The release marked xAI’s push into a coding-agent market OpenAI and Anthropic had led through 2025 and early 2026, with Cursor’s usage data now folded directly into a frontier lab’s training pipeline via outright acquisition rather than a data-sharing partnership.