xAI Releases Grok 4 and Grok 4 Heavy — Multi-Agent AI for $300/Month
Grok 4 ships as xAI's most intelligent model with native tool use. Grok 4 Heavy spawns multiple agents to solve problems in parallel. SuperGrok Heavy costs $300/month.
Alex Chen
xAI released Grok 4 and Grok 4 Heavy on July 9, 2025, with Grok 4 described as "the most intelligent model in the world." Grok 4 Heavy introduces multi-agent capabilities — spawning multiple AI agents that work on a problem simultaneously. A new SuperGrok Heavy subscription launched at $300/month for maximum access, according to xAI.
Grok 4: Native Tool Use
Grok 4 integrates tool use and real-time search natively, rather than as add-on capabilities. The model can search the web, query X data, execute code, and use external tools within a single response chain. This brings it closer to how Claude and GPT-5 handle tool integration.
Grok 4 Heavy: Multi-Agent Approach
Grok 4 Heavy is the headline feature — a multi-agent version that spawns multiple agents to work on different aspects of a problem simultaneously. Rather than one model reasoning sequentially, multiple instances coordinate in parallel.
This approach is similar to what Anthropic later shipped as agent teams in Opus 4.6, but Grok 4 Heavy arrived first. The $300/month SuperGrok Heavy subscription prices it as a premium product for professionals who need maximum AI capability.
The $200M Pentagon Contract
Two weeks after launch, xAI signed a $200 million contract with the U.S. Department of Defense for military AI applications. This positioned xAI alongside OpenAI (which has its own government contracts) as a defense AI provider, though the specific applications weren't disclosed.
Pricing
Consumer access: SuperGrok subscribers can use Grok 4, while Grok 4 Heavy requires the $300/month SuperGrok Heavy tier. API access was available through the xAI Enterprise API.
For comparison, Claude Pro costs $20/month and ChatGPT Pro costs $200/month. xAI's $300 SuperGrok Heavy is the most expensive consumer AI subscription available.
Our Take
Grok 4 Heavy arriving before Anthropic's agent teams is noteworthy — xAI beat a larger competitor to a feature that matters. The $300/month price tag is eye-catching but not unreasonable if multi-agent capability genuinely saves hours of professional work. The Pentagon contract legitimizes xAI as more than an X/Twitter feature. Whether Grok can maintain its position against the rapid iteration from OpenAI and Anthropic is the key question.
FAQ
What is Grok 4 Heavy? Grok 4 Heavy is xAI's multi-agent AI system that spawns multiple agents to work on different aspects of a problem simultaneously. It's available through the $300/month SuperGrok Heavy subscription.
How much does Grok 4 cost? Grok 4 is available through SuperGrok subscriptions. Grok 4 Heavy requires SuperGrok Heavy at $300/month. API pricing is available through the xAI Enterprise API.
Did xAI get a military contract? Yes, xAI signed a $200 million contract with the U.S. Department of Defense in July 2025 for military AI applications.