Composer and Devstral 2 (123B) don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Composer shipped 41 days before Devstral 2 (123B), so benchmark comparisons should account for the intervening progress.

Composer is proprietary, while Devstral 2 (123B) is open weight.

Direct benchmark comparisons are unavailable — Composer and Devstral 2 (123B) don't publish scores on any of the same benchmarks.