Musk's July 28 reply to @rauchg · 1.5T / 2.1T roadmap · SFT & RL focus · Kimi K3 pressure · unverified claims flagged
Summary: Elon Musk says Grok 4.6 is coming "around August 7," with a larger Grok 4.7 to follow a few weeks later. He shared the timeline on X on July 28, 2026, in a reply to Vercel CEO Guillermo Rauch—not in an official xAI announcement. No benchmarks, pricing, or model card have been published yet. This article separates what's on the record from vendor claims and industry leaks, with unverified details clearly marked.
Single-source risk: The only primary source is one X reply—no xAI blog post, model card, or pricing page yet
"Musk time" slips: xAI, Tesla, and SpaceX timelines have historically slipped by days to weeks
Compressed evaluation windows: Kimi K3 just went fully open-weight; rumored Claude Fable 5.1 also points to August
Benchmarks and pricing are blank: Unlike Grok 4.5's detailed model card, 4.6/4.7 have zero third-party verification
Safety headlines persist: xAI's July CSAM lawsuit and child-safety ratings matter for enterprise vendor risk, separate from raw capability
| Date | Event |
|---|---|
| July 8, 2026 | xAI ships Grok 4.5—coding/agentic focus, co-trained with Cursor on real developer sessions. 500K context, $2/$6 per million input/output tokens, published model card with 15 benchmark scores |
| July 16–26, 2026 | Moonshot AI's Kimi K3 goes from hosted preview to fully open-weight release (2.8T params, 1M context), topping Hugging Face trending; Musk praised it in benchmark comment threads |
| July 28, 2026 | Musk posts the Grok 4.6/4.7 roadmap replying to Rauch. Same day, 1,200+ employees at OpenAI, Anthropic, Google DeepMind, and Meta publish the "Pacing the Frontier" letter |
| ~August 7, 2026 (target) | Grok 4.6, 1.5T parameters, positioned as an SFT/RL upgrade rather than a raw scale-up |
| Late Aug–early Sep 2026 (est.) | Grok 4.7, 2.1T parameters—Musk says "better than 4.6 in every way, except slightly slower to serve, albeit with even better token efficiency" |
| Model | Date | Parameters | Focus | Status |
|---|---|---|---|---|
| Grok 4.3 Beta | Apr 17, 2026 | Undisclosed | Baseline | Shipped |
| Grok 4.5 | Jul 8, 2026 | Undisclosed (single SKU) | Coding/agentic, Cursor co-training | Shipped, benchmarked |
| Grok 4.6 | ~Aug 7, 2026 | 1.5T | SFT/RL upgrade | Announced via tweet, unshipped |
| Grok 4.7 | ~late Aug–early Sep | 2.1T | Broad upgrade, better token efficiency | Announced via tweet, unshipped |
All Grok 4.6/4.7 figures are unverified vendor claims from a single social media post—treat them as directional, not confirmed specs.
Supervised fine-tuning (SFT) shapes behavior on curated examples; reinforcement learning (RL) teaches which action sequences work in real multi-step agentic tasks. Musk's "significantly improved SFT & RL" wording signals xAI is doubling down on the Grok 4.5 playbook: roughly 15,954 output tokens per SWE-Bench Pro task versus Opus 4.8's 67,020—a 4.2× efficiency gap credited to post-training on real Cursor developer sessions, not sheer model size.
Grok 4.6's jump to 1.5T is a real scale increase, but Musk framing 4.7 as bigger (2.1T) yet "better in every way except slightly slower to serve" suggests two SKUs with different latency/quality trade-offs—similar to Anthropic's Sonnet/Opus split or OpenAI's mini/full tiers.
The competitive backdrop: Grok 4.6's target lands ~10 days after Kimi K3's open-weight shock. K3 topped Frontend Code Arena at 1,679 points—first open-weight model to beat every closed model on that board—and ranks third on Artificial Analysis's Intelligence Index. Chinese financial outlets reported massive market-cap sentiment swings around the release; those are analyst estimates relayed through media, not independently confirmed by the companies involved.
| Model | Vendor | Parameters | Context | Pricing (in/out per 1M) | Source |
|---|---|---|---|---|---|
| Grok 4.5 | xAI | Undisclosed | 500K | $2 / $6 | xAI official |
| Grok 4.6 (announced) | xAI | 1.5T | Undisclosed | Undisclosed | Musk's X post (unverified) |
| Kimi K3 | Moonshot AI | 2.8T MoE (~16/896 active) | 1M | $0.30 cache hit / $3 miss in, $15 out | Moonshot + Hugging Face |
| Claude Fable 5.1 (rumored) | Anthropic | Undisclosed | Undisclosed | Rumored Fable 5 ($10/$50) | 36kr, WinCentral—unconfirmed |
| GPT-5.6 Sol | OpenAI | Undisclosed | Undisclosed | Undisclosed | OpenAI official |
If Musk's timeline holds, Grok 4.6 and 4.7 land in the same month as rumored Claude Fable 5.1 (leaks from 36kr and WinCentral, timed to beat anticipated GPT-6) and just weeks after Kimi K3's open-weight shock. For teams evaluating models, useful shelf life of any single flagship compresses to weeks—making token efficiency and real-world task cost, not leaderboard rank alone, the more durable basis for choice.
Freeze your Grok 4.5 baseline: Log task types, token usage, and per-task cost in Cursor/API for apples-to-apples comparison
Watch official xAI channels: x.ai/news and @xai—not just X replies
Track Kimi K3 and Fable 5.1 rumors in parallel: August may be a three-way race—rank your scenarios (coding, agents, long context, cost)
Stage an isolated test environment: Week-one API volatility, quotas, and pricing shifts are common
Validate Cursor integration in a macOS GUI session: Grok 4.5 was co-trained with Cursor; 4.6 will likely land there first—model switching and Keychain prompts need a real Mac desktop, not SSH-only
Citable figures: Grok 4.5 at $2/$6 per M tokens · 4.6 target 1.5T · 4.7 target 2.1T · Kimi K3 Frontend Code Arena 1,679 · Grok 4.5 ~15,954 vs Opus 4.8 ~67,020 output tokens per SWE-Bench Pro task.
Musk said "around August 7, 2026" in an X post, but xAI has not officially confirmed a date. Treat it as a target that could shift.
Grok 4.6 is 1.5T with SFT/RL post-training focus. Grok 4.7, a few weeks later, is 2.1T—Musk says it beats 4.6 everywhere except serving speed, trading latency for better token efficiency.
Too early to tell. Grok 4.6 has no published benchmarks; Kimi K3 has verified scores; Claude Fable 5.1 isn't officially confirmed by Anthropic.
Unknown. Grok 4.5 launched at $2/$6 per million input/output tokens—a reasonable reference, but xAI hasn't disclosed 4.6 pricing.
Expect Grok Build, xAI API, and console first, with third-party platforms like Cursor shortly after—based on Grok 4.5's rollout, not confirmed for 4.6.
Grok 4.6 is still a roadmap in a tweet, not a model card—but with Kimi K3's open-weight shock and an August pile-up looming, building a comparison baseline now beats chasing parameter headlines. If your daily driver is Windows or Linux but you need to switch Grok models in Cursor, run agent benchmarks, or parallel iOS builds, buying a Mac is expensive and SSH-only sessions can't click Keychain or system permission prompts. Renting a VNCMac remote Mac gives you an hourly VNC desktop to validate Grok and OpenClaw multi-model workflows in isolation. See Mac rental plans; background in our Grok 4.5 review and Kimi K3 open-weight guide.
Sources: xAI "Introducing Grok 4.5" and model card (media.x.ai), Musk's July 28, 2026 X post (reply to @rauchg), Chain Tech Daily / Tron Weekly coverage, Moonshot AI releases, Emergent.sh / WinCentral / 36kr on Fable 5.1 leaks, The Verge / TechTimes on "Pacing the Frontier," Ars Technica / TechCrunch on xAI safety controversies. Information current as of July 30, 2026—all Grok 4.6/4.7 details are vendor announcements or industry leaks; verify against official xAI channels before relying on any date, spec, or price.