Grok 4.6: Frontier Grade, Half the Price

Grok 4.6 claims to match GPT-5.6 Sol on the intelligence index everyone ranks these models by — at half the price the frontier charges. Five weeks after Grok 4.5's July 8 debut, SpaceXAI shipped again, and I read the eval table twice, because the interesting parts are not the headline.

August 12, 2026 · AI · LLM · Pricing · Model Reviews

So what is 4.6, exactly? A post-training refresh of Grok 4.5 — not a bigger brain, a better-behaved one. SpaceXAI focused the release on long-running agents and ambitious interactive work: staying with complex tasks across many steps, researching unfamiliar domains, structuring an app and iterating on it. The company says it now hits 61 on the Artificial Analysis Intelligence Index, tying GPT-5.6 Sol (61) and sitting one point behind Fable 5 (62). Grok 4.5 scored 56.

Grok 4.6 — announced August 12, 2026 (image: SpaceXAI / X)

The benchmark card, without the spin

Here's the full table from the launch post. Every number is vendor-reported — SpaceXAI's own runs, with competitor figures drawn from their published system cards — so treat it as the company's best case, not an independent verdict:

Benchmark	Grok 4.6	Grok 4.5	GPT-5.6 Sol	Fable 5
AA Intelligence Index	61	56	61	62
GDPVal-AA v2	1753	1526	1728	1741
CursorBench v3.2	69.9%	66.7%	67.2%	70.5%
DeepSWE v1.1	65.9%	54%	73%	70%
FrontierCode v1.1 (Extended)	61.3%	56.6%	60.6%	63.6%
APEX-Agents	57.5%	47.1%	56.7%	59.2%
Terminal-Bench v3.0	26%	15.7%	34.6%	34.1%
Harvey LAB (Vals)	15.8%	12.9%	2.5%	11.3%
APEX-SWE	56.4%	53.6%	—	58.8%

Selected evals from the Grok 4.6 launch post (vendor-reported; best score per row in green)

Grok 4.6 vs 4.5 vs GPT-5.6 Sol vs Fable 5 — selected agentic benchmarks (vendor-reported)

The headline holds up: on the AA Intelligence Index — a composite of nine benchmarks — 4.6 really does match GPT-5.6 Sol (61). It beats both GPT-5.6 Sol and Fable 5 on GDPVal-AA v2 and the Harvey legal benchmark, and it beats GPT-5.6 Sol on CursorBench v3.2 — though Fable 5 edges it there, 70.5% to 69.9%.

But it's no clean sweep. On DeepSWE v1.1 (65.9% vs 73%) and especially Terminal-Bench v3.0 (26% vs 34.6%), the harder agentic-coding evals, GPT-5.6 Sol still wins clearly — and SpaceXAI isn't hiding those numbers.

And the jump from 4.5 is bigger than the +5 index points suggest. Look at APEX-Agents (47.1% → 57.5%) and DeepSWE (54% → 65.9%): the RL work landed where it was aimed, on long-running agentic behavior.

The price is the product

The price stayed exactly where 4.5 left it: $2 per million input tokens, $6 per million output — plus a fast variant at twice the price. Put that next to the models it just benchmarked against: GPT-5.6 Sol lists at $5/$30, and Fable 5 — the one model that actually beats it on CursorBench — at $10/$50. On output tokens, 4.6 costs roughly a fifth of Fable 5. SpaceXAI's whole pitch for this model line is that you don't have to choose between frontier scores and sane bills.

API pricing per 1M tokens (list prices, Aug 2026)

If you're comparing to 4.5's launch: same $2/$6 anchor, same availability playbook. Grok 4.6 is live today in Cursor, Grok Build, Grok Bot, and the API, with OpenRouter, Vercel, and Cloudflare listed as launch partners. And for the first week, Cursor and Grok Build users get 2x included usage — a practical heads-up if you were planning to stress-test it this weekend.

How they made it: the self-improvement loop

The training story is the most interesting part of the release. They gave 4.6 a longer finishing run than 4.5 — more curated data, a better training recipe. Then the clever bit: they had Grok 4.5 itself rewrite the practice answers (the SFT trajectories) across reasoning, agents, STEM, and coding, with model-based checks filtering out the bad traces. The previous model doing homework for the next one is a very 2026 training story, and it's apparently where the agentic gains came from — followed by RL in specialized environments like kernel optimization, web development, and computer-aided design.

The result, per the launch post: stronger first passes on visual and interactive projects, more self-testing on long trajectories (the model checking its own work before moving on), and a special strength at turning a broad product idea into a working first version. That's a very specific claim — give it a vibe, get a working app skeleton — and it reads like the team aimed 4.6 squarely at the Cursor/Grok Build crowd.

The cadence: 4.6 now, 4.7 in weeks

Context helps here. Musk first teased 4.6 on July 24 ("in 2 weeks"), then refined it on July 27: "the 1.5T model with significantly improved SFT & RL." The release landed today — five days after the "around August 7" target slipped, but inside the "next week" window he'd given on the August 4 earnings call. Grok 4.7 — the 2.1T scale-up, "better in every way, except slightly slower to serve" — is a few weeks behind. None of that changes the model, but it frames what to expect next: 4.6 is the same-size, better-trained refresh, and 4.7 is where the bigger brain shows up.

Five weeks from 4.5 to 4.6 — and 4.7 (2.1T) is already teased by Musk

My take

The honest read: 4.6 is a strong same-price upgrade with one clear caveat — it's not a clean sweep. If your workload is long agentic runs, knowledge work, or turning ideas into working apps, the eval deltas (APEX-Agents +10, DeepSWE +12, Harvey 15.8% vs GPT-5.6's 2.5%) are genuinely impressive at this price point. If your workload is hard terminal-based agentic coding, the Terminal-Bench gap says GPT-5.6 Sol still has the edge — 26% vs 34.6% is not a rounding error.

And the numbers are still the company's own. Artificial Analysis (Arena) announced on July 29 that Grok 4.6 will appear on its leaderboards the week after launch — that independent read is the first number that doesn't come from SpaceXAI, and it should land within days. I'll update this post when it does.

So that's 4.6: frontier-adjacent scores, half the price, already in Cursor and Grok Build, double usage for the first week. If you were waiting for a reason to test Grok seriously, this is the cheapest one yet — and 4.7 is coming right behind it, which makes the next few weeks genuinely fun to watch.

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