You can turn off thinking in Gemini pro models by using completion mode.

Essentially, append a message with role=model and minimal text part, such as a simple "A", at the end of the "contents" array. The model will try to complete the message without using any thought tokens.

You can also set the model message to start with "think" or something along that line and watch it thinks out loud (or melts down with over-thinking and stop due to reaching maximum output token)

``` [ { "parts": [{"text": "hello"}], "role": "user" }, { "parts": [{"text": "*think"}], "role": "model" } ] ```

TIL gemini still supports completion mode, that's super useful!

Thinking is just tacked on for Anthropic's models and always has been so leaving it off actually produces better results everytime.

What about for analysis/planning? Honestly I've been using thinking, but if I don't have to with Opus 4.6 I'm totally keen to turn it off. Faster is better.

I've always just used the "Plan mode" in Claude Code, I don't know if it uses thinking? I have "MAX_THINKING_TOKENS" in my settings.json set to "0", too. Didn't notice a drop in performance, I find it better because it doesn't overthink ("wait, let me try..."). Likely depends on a case-by-case basis (as so often with AI). For me, it's better without thinking.