Compare AI models

Specifications
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.
64.7%35%
Overview
CompanyAnthropicSpaceXSI
Release dateApr 7 2026Apr 17 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Mythos Preview leads Grok 4.3 Beta on 1 of the 1 benchmark they both report (Humanity's Last Exam). Claude Mythos Preview shipped 10 days before Grok 4.3 Beta, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

On Humanity's Last Exam · with tools, Claude Mythos Preview leads at 64.7% vs Grok 4.3 Beta at 35%.