harness won't matter after 8-12 months. it already makes a tiny difference and that gap will keep shrinking
imagine spending months optimizing harnesses in 2026 when you could be building things that actually compound: model routers, knowledge graphs, memory architectures, context engineering, evals, better prompting, and agent workflows
knowing which model to use for which task will matter far more than chasing benchmark decimals. Opus for complex reasoning, GPT for reliability, Kimi for long context, DeepSeek for cost, fast models for simple tasks. routing and orchestration will be the advantage, not squeezing another 0.5% out of a harness