Kimi K3

Muse Spark Open is the closest US replacement for Kimi K3, five index points behind and cheaper per task. Defense, nuclear and critical-infrastructure buyers should pick Apache 2.0 Reflection Beam instead.

Kimi K3 costs $3 / $15 at four of the five hosts compared that offer it and gpt-oss-120b $0.15 / $0.60 at four of six, but Moonshot's vendor audit found schema accuracy from 100% down to 71.96%. Fireworks is the default for agents; Together is the one to avoid for tool-heavy work.

Meta's 816B Muse Spark Open is free for internal use, but its license bans operating critical infrastructure and any nuclear or military use, the same clauses Llama 3 carried.

Mistral Large 4 beats Kimi K3 on Harvey's legal agent benchmark and trails it on the Vals Index. It is a discounted preview API for now, and the licence for its end-of-October weights is unpublished.

Reflection's Beam is a 501B Apache 2.0 open model from a US lab, and its own table has it losing to Kimi K3 on 13 of 14 shared benchmarks. Weights and pricing aren't out yet.

Harvey sold flat seats on top of a metered model bill, and agent usage drove its gross margin to -50% by June. The margin recovered after it launched its own Kimi K3-based model, with no reported price change, so renewals of agentic AI seats need model-change and usage terms.

Thomson Reuters' new in-house legal model is a Qwen derivative two hops down, and Harvey's Tenet is post-trained from Kimi K3. Neither lineage appears in a DPA or a subprocessor list — because an open-weight base model provider processes nothing.

One of the first multi-vendor serving benchmarks on Kimi K3 puts AMD's MI355X at roughly 1.5x Nvidia B300's tokens per dollar — but that rests on a $2.50/GPU-hour rate you cannot currently buy. At the only purchasable on-demand rates, the gap narrows to 6%.