Compare AI models

Specifications
Parameters
—117B
Context window
1M128k
API pricing
Cheapest input
—$0.03CoreWeave
Cheapest output
—$0.17CoreWeave
Benchmarks
SWE-Bench Verified
95.5%62.4%
Humanity's Last Exam · with tools
64.5%19%
Overview
CompanyAnthropicOpenAI
Release dateJun 9 2026Aug 5 2025
AccessClosedOpen Weight
Model detailsView modelView model

Frequently asked questions

Claude Mythos 5 leads gpt-oss-120b on 2 of the 2 benchmarks they both report (SWE-Bench Verified, Humanity's Last Exam). gpt-oss-120b shipped 308 days before Claude Mythos 5, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Mythos 5) vs 128k (gpt-oss-120b). Claude Mythos 5 is closed, while gpt-oss-120b is open weight.

On SWE-Bench Verified, Claude Mythos 5 leads at 95.5% vs gpt-oss-120b at 62.4%. On Humanity's Last Exam · with tools, Claude Mythos 5 leads at 64.5% vs gpt-oss-120b at 19%.