Kimi K3 vs Grok 4.6

What I tested — same prompt, two models

I run the same fixed prompt set through every new model the day it drops — same string, one shot, single HTML file out — and I score the result 0–10 on whether it ran, how close it hit the brief, and how good it looked. Below is what came out when I gave the exact same prompts to Kimi K3 and Grok 4.6, side by side, on 20 shared tasks inside the Agent Operating System.

Both models were given identical prompts inside the Agent Operating System — no help, no iteration, no "best of N" tricks. I run each prompt once, save the HTML file the model produces, and score it 0–10 on whether it ran, how close it hit the brief, and how good it looked. The scoring is mine. The verdicts below are pulled from my source comparison guides at agentos.guide where I publish every score and the reasoning behind it.

Kimi K3 · Wired into the Agent OS as the `kimi-k3` Hermes profile and a K3 speed-toggle in the Kimi Code tab — used for long unattended agent runs where a slow-but-right model beats a fast-but-forgetful one.

Grok 4.6 · Benched on 16 skill-infused game builds, every one played through its full gameplay arc before scoring, then the broken ones were handed back to Grok 4.6 to repair itself.

Where Kimi K3 beat Grok 4.6

The tasks where I gave Kimi K3 a higher 0–10 score on the same prompt — with the actual commentary from my source guides.

Where Grok 4.6 beat Kimi K3

The tasks where I gave Grok 4.6 a higher 0–10 score on the same prompt — with the actual commentary from my source guides.

Strengths & weaknesses I logged

Pricing & context — the spec sheet

The verdict — which should you pick?

Across 20 scored shared tasks, Kimi K3 averaged 8.07/10, beating Grok 4.6's 5.95/10 by 2.12 points. Pick Kimi K3 when the build has to ship on the first prompt and you can afford the trade-offs in the comparison below.

If you only run one of these inside your stack, the head-to-head average above is the call. If you can run both, my honest play is to wire Kimi K3 and Grok 4.6 both into the Agent Operating System and dispatch each from the kanban by task type — long-horizon agent runs → Kimi K3, high-volume agent work where the per-token bill decides what you can afford to run → Grok 4.6. That's the same setup I run for the 4,000+ founders inside the AI Profit Boardroom.

FAQ — Kimi K3 vs Grok 4.6

Which is better, Kimi K3 or Grok 4.6?

On Goldie Bench, Kimi K3 averages 8.07/10 across the shared tasks, with 8 gold, 4 silver, 7 bronze overall. Grok 4.6 averages 5.95/10, with 1 gold, 0 silver, 0 bronze. Kimi K3 wins the head-to-head 16–3.

How much does Kimi K3 cost vs Grok 4.6?

Kimi K3: Launched July 16, 2026. 2.8T-param MoE (Moonshot's quickstart corrected the circulating 2.5T estimate). $3/M input on OpenRouter at launch; included at no extra cost in the Kimi coding plan (`k3` on the coding endpoint). Grok 4.6: xAI's August 2026 flagship. $2 per million input tokens and $6 per million output tokens on the standard tier (the Fast tier is double), which is roughly half what the other frontier models charge for the same Artificial Analysis Intelligence Index score of 61.

What's the context window for Kimi K3 vs Grok 4.6?

Kimi K3 has a 1,048,576 tokens — a full codebase in working memory context window. Grok 4.6 has a 500,000 tokens context window.

When should I pick Kimi K3 over Grok 4.6?

Pick Kimi K3 for: long-horizon agent runs; whole-repo context work; terminal-driving agents. The trade-off is the weaknesses we logged on the bench: Slow on hard tasks — early testers report up to ~35 minutes at max reasoning; this bench saw 13+ minute single builds; Launch-day rate limits on OpenRouter (429s) — the coding-plan endpoint was the reliable route; Self-reports as K2.7 if you ask it — verify the served model via the API response, not the model's word.

When should I pick Grok 4.6 over Kimi K3?

Pick Grok 4.6 for: High-volume agent work where the per-token bill decides what you can afford to run; Arcade, shooter and driving builds in one shot; Self-repair loops - it is unusually good at fixing a build when you hand it the real error. The trade-off is the weaknesses we logged on the bench: Flight models are its weak spot: both the flight sim and the dogfight shipped unflyable on the first pass; Two of sixteen game builds died on a hard error (a duplicate identifier and a bad computeBoundingSphere call); Worlds are lit and composed but usually untextured, so terrain reads as flat coloured planes.

How does Goldie Bench score Kimi K3 vs Grok 4.6?

Every demo on this page was built by Julian Goldie inside the Agent Operating System — same fixed prompt for both models, one shot, single HTML file out. Each result gets a 0–10 score on whether it ran, how close it hit the brief, and how good it looked. The highest score on each task gets gold; second gets silver; third gets bronze. See methodology for full provenance.

Related comparisons

Other head-to-heads using the same scoring system:

Full model pages: Kimi K3 · Grok 4.6 · back to the leaderboard