GPT-5.6 Sol vs Grok 4.20

Choose GPT-5.6 Sol if you want hard coding and research tasks for teams in the OpenAI ecosystem. Choose Grok 4.20 if you want agents that genuinely need 2M tokens of context.

In our editorial scoring, GPT-5.6 Sol leads in 3 of five dimensions (output quality, agentic ability and reliability), while Grok 4.20 leads in 2. On price, GPT-5.6 Sol runs about $13 per 1M tokens (blended) and is proprietary; Grok 4.20 is about $1.63 and proprietary.

The model is half the story — the agent is the other half

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.