Elon Musk posted two brief updates on June 5 confirming a core model improvement to Grok and the addition of worktrees support — but those two tweets are just the visible tip of a much larger wave of xAI releases. Here's the full picture of what's shipping right now.
1. Core Model Gets a Meaningful Upgrade
The model improvement Musk referenced points to ongoing work on Grok V9-Medium, which completed training at 1.5 trillion parameters — three times the size of the current v8-small production model at 500 billion parameters. According to verified reports, supervised fine-tuning and reinforcement learning were already underway as of late May, with a public release expected in mid-June 2026. For everyday users, this translates to sharper reasoning, better code output, and more reliable responses across complex queries.
2. Worktrees Support Unlocks Parallel Coding Workflows
The second tweet confirms Grok now supports worktrees — a Git feature that allows multiple working directories from a single repository. In practice, this means Grok's coding subagents can work on parallel branches simultaneously without touching the main codebase. It's a significant workflow improvement for developers using Grok Build 0.1, the dedicated coding model released to public beta on May 29, 2026. Isolated worktrees reduce the risk of one agent's edits breaking another's work mid-task.
3. Grok Build 0.1 Is Now Open to Developers
Available via the xAI API in public beta since May 29, Grok Build 0.1 is a dedicated coding model built for agentic tasks. It carries a 256,000-token context window, always-on reasoning, and accepts both text and image inputs. Pricing is straightforward: $1 per million input tokens and $2 per million output tokens. The worktrees support Musk highlighted is native to this model, making it the most capable coding tool xAI has shipped to date.
4. Grok Voice and Imagine 1.5 Launched Yesterday
Just one day before these tweets, on June 4, xAI publicly rolled out Grok Voice — spoken interaction with the model — alongside Grok Imagine 1.5 Preview, now available via API. Imagine 1.5 debuted at number one on the Artificial Analysis Video Arena Image-to-Video leaderboard with an Elo rating of 1404, generates native synchronized audio, and extends clip lengths to 15 seconds. The back-to-back release cadence suggests xAI is running coordinated launch sprints rather than drip-feeding features.
5. Much Larger Models Are Already in the Pipeline
The model improvements shipping now are a warm-up. According to previous announcements, Grok 4.4 at 1 trillion parameters and Grok 4.5 at 1.5 trillion parameters are expected within weeks. Beyond that, Grok 5 is currently in training on xAI's Colossus 2 supercluster in variants reaching 10 trillion parameters — a scale that would dwarf anything currently in public deployment. No confirmed release date exists for Grok 5, but the infrastructure is clearly being built out at pace.
The two tweets Musk posted this morning are easy to scroll past, but they reflect a company shipping at an unusually high cadence across models, APIs, voice, and video generation simultaneously. For Tesla owners who use Grok through the in-car interface or the X app, the practical improvements — faster reasoning, better code help, voice interaction — are already arriving or weeks away.
Sarah focuses on Tesla Energy, SpaceX missions, and the broader Musk AI portfolio. Former data analyst in clean energy. Based in San Francisco.
Sources verified at publish time. Spotted an inaccuracy? Email editorial@basenor.com.
