Compare AI models

Specifications
ParametersThe learned values that shape how a model responds. B means billion and T means trillion. For mixture-of-experts models, the total count is larger than the number active for each token. Parameter count alone does not measure quality.
—2.8T
Context windowHow much information the model can work with in one request, measured in tokens — pieces of words or other data. This includes your question, attachments, conversation and reply. Limits can vary by model variant and provider.
—1M
Benchmarks
Humanity's Last Exam · with toolsMultidisciplinary reasoning — Humanity's Last Exam — extremely hard expert questions across many subjects. “With tools” means the AI is allowed to search the web or run code while answering. Higher is better.
50.4%70%
Overview
CompanyMetaMoonshot AI
Release dateApr 8 2026Oct 23 2026
AccessClosedOpen Weight
Model detailsView modelView model

Frequently asked questions

Kimi K3.1 Pro leads Muse Spark on 1 of the 1 benchmark they both report (Humanity's Last Exam). Muse Spark shipped 198 days before Kimi K3.1 Pro, so benchmark comparisons should account for the intervening progress.

Muse Spark is closed, while Kimi K3.1 Pro is open weight.

On Humanity's Last Exam · with tools, Kimi K3.1 Pro leads at 70% vs Muse Spark at 50.4%.