GPT-5.6 Terra Pro is the same underlying model as [GPT-5.6 Terra](https://openrouter.ai/openai/gpt-5.6-terra), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. Learn more in OpenAI's docs: https://de…
Model details →OpenAI: GPT-5.6 Terra Pro vs SpaceXAI: Grok 4.20 Multi-Agent
OpenAI: GPT-5.6 Terra Pro and SpaceXAI: Grok 4.20 Multi-Agent are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
Grok 4.20 Multi-Agent is a variant of SpaceXAI’s Grok 4.20 designed for collaborative, agent-based workflows. Multiple agents operate in parallel to conduct deep research, coordinate tool use, and synthesize information...
Model details →Side-by-side comparison
| Capability | OpenAI: GPT-5.6 Terra Pro | SpaceXAI: Grok 4.20 Multi-Agent | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 1.1M | 2M | 🏆 SpaceXAI: Grok 4.20 Multi-Agent |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $1.00 | $1.25 | 🏆 OpenAI: GPT-5.6 Terra Pro |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $6.00 | $2.50 | 🏆 SpaceXAI: Grok 4.20 Multi-Agent |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | — | 🏆 OpenAI: GPT-5.6 Terra Pro |
| Vision input Accepts image inputs alongside text. | Yes | Yes | Tie |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is OpenAI: GPT-5.6 Terra Pro better than SpaceXAI: Grok 4.20 Multi-Agent?
OpenAI: GPT-5.6 Terra Pro and SpaceXAI: Grok 4.20 Multi-Agent are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
What's the price difference between OpenAI: GPT-5.6 Terra Pro and SpaceXAI: Grok 4.20 Multi-Agent?
Input: $1.00 vs $1.25 per 1M tokens. Output: $6.00 vs $2.50 per 1M tokens.
What context windows do OpenAI: GPT-5.6 Terra Pro and SpaceXAI: Grok 4.20 Multi-Agent support?
OpenAI: GPT-5.6 Terra Pro supports up to 1.1M tokens. SpaceXAI: Grok 4.20 Multi-Agent supports up to 2M tokens.
Do both OpenAI: GPT-5.6 Terra Pro and SpaceXAI: Grok 4.20 Multi-Agent support tool calling?
OpenAI: GPT-5.6 Terra Pro: yes. SpaceXAI: Grok 4.20 Multi-Agent: not advertised.
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