Side-by-side technical and economic comparison between Anthropic's Claude Fable 5.1 and xAI's Grok 2 mini.
• Grok 2 mini: Classified as a Legacy Reference model (Generally Available).
| Metric | Claude Fable 5.1 | Grok 2 mini | Advantage |
|---|---|---|---|
| Provider Organization | Anthropic | xAI | — |
| Standard Input / 1M | $10.00 | $0.20 | Grok 2 mini (98% lower) |
| Cached Input / 1M | $0.25 | None | Grok 2 mini lower |
| Output / 1M | $50.00 | $1.00 | Grok 2 mini lower |
| Context Window | 1M | 128k | Claude Fable 5.1 (1M) |
| Max Generation Tokens | 32k | 8.2k | Claude Fable 5.1 |
| Tokenizer Family | Anthropic Claude BPE (~65k vocabulary) | xAI Byte-level BPE (~131k vocabulary) | — |
Opt for Claude Fable 5.1 when your engineering requirements prioritize Anthropic's ecosystem, specific tokenizer efficiencies (Calibrated Claude Tokenizer (±3%)), or when your expected prompt-to-completion ratios favor its $10/M input rate.
Opt for Grok 2 mini when looking for xAI's tooling integration, specific context window depth (128k tokens), or when output generation volume favors its $1/M rate.