Side-by-side technical and economic comparison between OpenAI's OpenAI o1 and Anthropic's Claude Fable 5.1.
| Metric | OpenAI o1 | Claude Fable 5.1 | Advantage |
|---|---|---|---|
| Provider Organization | OpenAI | Anthropic | — |
| Standard Input / 1M | $15.00 | $10.00 | Claude Fable 5.1 (33% lower) |
| Cached Input / 1M | $7.50 | $0.25 | Claude Fable 5.1 lower |
| Output / 1M | $60.00 | $50.00 | Claude Fable 5.1 lower |
| Context Window | 200k | 1M | Claude Fable 5.1 (1M) |
| Max Generation Tokens | 100k | 32k | OpenAI o1 |
| Tokenizer Family | OpenAI o200k_base (200k vocabulary) | Anthropic Claude BPE (~65k vocabulary) | — |
Opt for OpenAI o1 when your engineering requirements prioritize OpenAI's ecosystem, specific tokenizer efficiencies (Exact BPE (o200k_base)), or when your expected prompt-to-completion ratios favor its $15/M input rate.
Opt for Claude Fable 5.1 when looking for Anthropic's tooling integration, specific context window depth (1M tokens), or when output generation volume favors its $50/M rate.