Personally, with our company on Cursor, I can see why model makers are not the best people to go all the way down the stack. Using the right model for the situation will continue to be important, and model makers, by design, do not want to give you the choice to run different models.

Right now, we use:

- Kimi K2.5 for easy fixes, asking about the code, various agentic commands (e.g., summarizing Loom videos for Slack messages)

- Opus 4.8, Sonnet, or Kimi for planning (we find GPT-5.5 to have too terse outputs for plans)

- Kimi K2.5, Composer 2.5, GPT-5.4 mini, etc. for faster implementation (i.e. we don't have to wait around for the slower tokens-per-second generation on Sonnet, etc.)

If we had to only use Opus, Sonnet, and Haiku, I'd definitely be looking to switch harnesses