Pick a winner in each dimension — change your vote anytime.
Pricing and capabilities synced from the OpenRouter catalogue. Scores are editorial (0–10).
Choose Gemini 3.1 Pro if you want huge-context and multimodal work, and Gemini CLI users. Choose GPT-5.5 if you want hard reasoning and coding for teams in the OpenAI ecosystem.
In our editorial scoring, GPT-5.5 leads in 3 of five dimensions (output quality, agentic ability and reliability), while Gemini 3.1 Pro leads in 2. On price, Gemini 3.1 Pro runs about $5.00 per 1M tokens (blended) and is proprietary; GPT-5.5 is about $13 and proprietary.
The model picks the moves; the agent runs the loop, the tools, and the guardrails. Once you've chosen a model, see which agent gets the most out of it.