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Kimi K3.1's 'Chasing Astra' Headlines Meet a 13% Terminal-Bench Reality

By 怕浪猫 ·
Read original on juejin.cn ↗ Google Translate ↗ Alt translation

Choosing a model on launch-week headlines is the trap: today's K3 fails 87% of Terminal-Bench 4.0 tasks that require finishing work in a real terminal, and the $2.00 per-task cost with 37 tok/s output fails any cost or latency bar in production. The reporting also shows why benchmark versions matter — AA's v4.3 re-run dropped unchanged models by up to 6 points, so any team comparing absolute AI scores must pin the version or the comparison is meaningless.

Summary

On October 22, unclaimed models Kibitz and Kalmia appeared in Arena.ai's Code Arena, and four outlets ran headlines saying Kibitz's performance chases GPT-6 Astra. The community's case for Kibitz being Moonshot's Kimi K3.1 relies on three indirect trails: a tokenizer fingerprint test where Kibitz garbled all 11 Moonshot-identifying tokens, an official Kimi API config leak containing a 'k3.1' session target that was later pulled, and release-timing signals. No Arena Elo is public, so no hard number supports the claim yet.

The measurable numbers come from Artificial Analysis' intelligence index v4.3.2. K3 scores 44 against Astra's 53, a 9-point gap that actually spans 7 models and 20 configuration tiers, with no Chinese model above 50 points. The sharper problem sits in Terminal-Bench 4.0, where K3 lands at 13% against Astra's 59% — 4.5x worse — while beating Astra by 3 points on SciCode. That lopsided profile means the weakness is chained, real-environment execution, exactly the capability agent products need. The same run exposes K3 at $2.00 per task (15x more than same-score MiMo-V2.6-Pro) and 37 tok/s, ranked 72nd of 78; AA calls it 'notably slow.'

Takeaways
— K3 scores 13% on Terminal-Bench 4.0 versus GPT-6 Astra's 59%, a 4.5x gap, while beating Astra by 3 points on SciCode.
— K3 got 44 on Artificial Analysis' v4.3.2 intelligence index, with 20 configuration tiers and 7 models sitting between it and Astra's 53.
— No Chinese model has broken 50 points on the v4.3 index; the highest is Xiaomi MiMo-V2.6-Pro at 46.
— K3 costs $2.00 per task at max settings; same-score MiMo-V2.6-Pro costs $0.13 and Step 5 Preview $1.03.
— K3 outputs 37 tokens per second, ranked 72nd of 78 models on AA's page, which calls it 'notably slow.'
— AA's v4.3 revision upgraded Terminal-Bench 2.1 to 4.0, replaced τ³-Banking with Zapier-built AutomationBench-AA (657 private tasks), and raised private-benchmark weight from 40% to 45%, dropping industry scores by 1.85 to 6.17 points.
— The community claim that Kibitz costs 1/14 of Astra per token doesn't match official prices ($3/$15 vs $10/$50 per million tokens, about 1/3); per-task, K3 is only 39% cheaper than Astra at $2.00 vs $3.26.
— Moonshot AI suspended new subscriptions within 48 hours of K3's July launch after requests 'far exceeded predictions' and is preparing for a Hong Kong IPO within roughly six months.
— AA's v4.3 day had GLM-5.3 and K3 tied at 44 as the open-weight leaders; two months later the open-source leader is MiMo-V2.6-Pro at 46.
— K3 price output at ¥100 per million tokens, 10x+ DeepSeek V4-Pro and MiMo-V2.5-Pro prices, 3.5x GLM-5.2, 2.8x Qwen3.7-Max.
Conclusions

The 'chasing Astra' framing rests on three indirect evidence trails, one of which was withdrawn, and no Arena Elo is public; the gap between the press headline and what any grader can verify is the actual story — the model may be excellent, but the claim isn't supported yet.

K3's lopsided profile — ahead of Astra on SciCode, 4.5x behind on Terminal-Bench — places the deficit exactly where agent work happens: chaining steps through a real environment. That makes the 13% the number to watch, not the 9-point index gap.

The $2.00 per-task cost and 37 tok/s output are chip problems, not model problems, so a software update won't fix them. That connects directly to Moonshot's IPO prep: a company that already rate-limited users once after K3 launched cannot afford to repeat that while raising capital.

AA's v4.3 score drops across every lab show that benchmark revisions can wipe out a version's worth of apparent progress; any absolute score quoted without a version number is a number without a scale.

Concepts & terms
Terminal-Bench 4.0
A public benchmark that hands an agent a real terminal with 66 tasks across seven domains (software, machine learning, science, operations, security, hardware, media) and measures whether it actually completes the work. Scored as pass@1 averaged over three runs, it is the closest public measure to real computer operation.
Artificial Analysis Intelligence Index
A single-number capability score produced by Artificial Analysis, which publishes all raw scores. Version v4.3.2 weights ten benchmarks across Agent work (30%), general tasks (30%), programming (20%), and scientific reasoning (20%). The v4.3 revision made benchmarks harder and dropped most models' scores by 2 to 6 points.
Tokenizer fingerprint
A technique using special tokens that only one model family's tokenizer encodes correctly. Having an anonymous model garble all 11 Moonshot-identifying tokens, while seven other labs' models reproduce them exactly, is strong evidence the model belongs to Kimi's lineage.
From the discussion
Featured comments
随风鲈鱼

This whole article is AI-generated, right? The AI flavor is extremely strong (facepalm)

怕浪猫

A big spoon of beef bone broth paste, brewed with 3L of plain water, so it's extremely strong (grin)

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