Composer 1.5 and GPT-5.6 Terra don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Composer 1.5 shipped 138 days before GPT-5.6 Terra, 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.

Direct benchmark comparisons are unavailable — Composer 1.5 and GPT-5.6 Terra don't publish scores on any of the same benchmarks.