Constant REASONING_MODELS 

pub const REASONING_MODELS: &[&str];

Models that support thinking/reasoning capability with configurable thinking_level Based on: https://ai.google.dev/gemini-api/docs/gemini-3 Gemini 3 Pro: supports low, high Gemini 3 Flash Preview: supports minimal, low, medium, high Gemini 3.7/3.8 Flash: supports low, medium (default), high — minimal not supported on 3.8 and will error