coding is basically solved for the boring 90% of tasks

just mass refactored a 120 file FastAPI service. 400 steps, 2M tokens, $3 total, zero human input. it confidently introduced a deadlock into my async event handler which was genuinely funny, so the hard 10% still needs opus. ran deepseek v4 and Hunyuan Hy3 preview as the cheap workers. 21B active params, roughly $0.18 per million input tokens, about 80x cheaper than opus. Tencent reports 99.99% step success across 495 step production runs and that honestly tracked for routine refactors in my case. what caught me off guard was latency: the open weight tier responded faster than opus, so the 360 easy steps finished in under an hour while the 40 escalations took almost as long.