Pyyan / Compare / Step 5 Preview vs Claude Fable 5
Step 5 Preview vs Claude Fable 5
2 of 5Language Models · verified 20 Sept 2026
Step 5 PreviewStepFuncurrentClaude Fable 5Anthropiccurrent
| Specification | Step 5 Preview | Claude Fable 5 |
|---|---|---|
| Summary | A frontier tier score at a tenth of the frontier price. | Most capable widely released model, for the hardest reasoning and long-horizon agentic work. |
| Context | 1M | 1M |
| Input ($/Mtok) | $1 | $10 |
| Output ($/Mtok) | $2.7 | $50 |
| Licence | Proprietary | Proprietary |
| Max output | Not published | 128K |
| Parameters | 600B total, 27B active | — |
| Released | 18 Sep 2026 | — |
| Model ID | step-5-preview | claude-fable-5 |
| Category | Language Models | Language Models |
| Official | StepFun ↗ | Anthropic ↗ |
Highlighted rows are where these differ.
Step 5 Preview
- 600B total parameters with 27B active per token, text and images in
- 24th of 200 models on the Artificial Analysis intelligence index
- Listings disagree on context: 1M on StepFun's API and Artificial Analysis, 100K on some trackers
Best for cheap reasoning at volume.
Claude Fable 5
- Thinking is always on — the `thinking` param is rejected
- Raw chain of thought is never returned
- Requires 30-day data retention; unavailable under ZDR
Best for the hardest problems.