Which AI model handles the longest context window?
Gemini 3.1 Pro and Gemini 2.5 Pro both support 1 million token context windows — the largest available. This lets you feed in entire codebases, long legal documents, or complete books. Claude Fable 5 supports 200K tokens and GPT-5.4 supports 128K tokens, both sufficient for most use cases.
Context window comparison (2026)
| Model | Context window | Best for |
|---|---|---|
| Gemini 3.1 Pro | 1M tokens | Entire codebases, very long docs |
| Gemini 2.5 Pro | 1M tokens | Analysis, reasoning over huge inputs |
| Claude Fable 5 | 200K tokens | Long documents, multi-file coding |
| Claude Sonnet 4.6 | 200K tokens | Standard large-context tasks |
| GPT-5.4 | 128K tokens | Most use cases |
| GPT-5.5 | 128K tokens | Maximum reasoning |
| Llama 4 | 128K tokens | Open-weight large context |
When you need a long context window
- Codebases — feeding an entire repo to the model for architectural review
- Legal/contracts — analyzing a full contract or RFP
- Research papers — summarizing a 200-page report
- Books/manuscripts — editing or Q&A over a full book
All models listed are available on Kunya. Switch between them with one click.