We ran Composer 2.5 and 2.5 Fast across 11 skills. Surprisingly, Fast won.
Cursor just shipped Composer 2.5 and Composer 2.5 Fast. We benchmarked both across 11 engineering skills, 5 scenarios per skill, averaged across three independent LLM judges. The fast model scored higher, ran 32% quicker, and costs exactly the same. If you are reaching for Composer 2.5 over Composer 2.5 Fast, you are paying the same price for a slower, slightly worse model. Here is the full picture. TL;DR Composer 2.5 Fast scores 92.7% with skill context. Composer 2.5 scores 92.1%. Fast wins. Both are ahead of gpt-5.5, gpt-5.4, and the previous Composer 2. The fast model completes scenarios in 59 seconds on average. The regular model takes 87 seconds. Where They Land in the Benchmark We ran 6 models across 11 skills, scoring each run with three independent judges and averaging the results. Here is where the full leaderboard sits: Model Avg baseline Avg with-skill Lift opus-4-7 80.8% 93.4% +12.6 composer-2.5-fast 79.6% 92.7% +13.1 composer-2.5 79.0% 92.1% +13.1 composer-2 74.2% 89.6% +15.4 gpt-5.5 75.5% 89.4% +13.9 gpt-5.4 74.1% 89.3% +15.2 gpt-5.3 65.5% 83.9% +18.4 gpt-5-codex 68.7% 78.7% +10.0 Composer 2.5 Fast sits 1.3 points behind opus-4-7 and 3.3 points clear of everything else. That is a meaningful gap. The previous Composer 2 sits alongside gpt-5.4 and gpt-5.5 at roughly 89-90%. Cursor has moved its own model up a full competitive tier in a single release. The Fast model seems better. Normally a "fast" variant trades quality for speed. Composer 2.5 Fast does not do that. It scores 0.6 points higher than the regular model while running 28 seconds faster per scenario (59s vs 87s on average across 110 scored runs). The per-skill breakdown shows where the differences accumulate: Skill 2.5 with-skill 2.5-fast with-skill Winner documentation 97% 98% fast fastify 99% 94% 2.5 init 87% 86% 2.5 linting 98% 99% fast node-best-practices 95% 95% tie nodejs-core 98% 98% tie oauth 92% 89% 2.5 octocat 95% 96% fast skill-optimizer 98% 98% tie snipgrapher 93% 93% tie typescrip