Pyyan / Compare / o3 / o4-mini vs Claude Fable 5
o3 / o4-mini vs Claude Fable 5
2 of 5Language Models · verified 13 Aug 2026
o3 / o4-miniOpenAIretiredClaude Fable 5Anthropiccurrent
| Specification | o3 / o4-mini | Claude Fable 5 |
|---|---|---|
| Summary | The o-series reasoning line, retired Feb 2026. | Most capable widely released model, for the hardest reasoning and long-horizon agentic work. |
| Context | — | 1M |
| Input ($/Mtok) | — | $10 |
| Output ($/Mtok) | — | $50 |
| Licence | Proprietary | Proprietary |
| Max output | — | 128K |
| Model ID | — | claude-fable-5 |
| Category | Language Models | Language Models |
| Official | OpenAI ↗ | Anthropic ↗ |
Highlighted rows are where these differ.
o3 / o4-mini
- Reasoning is now an effort setting on GPT-5.x, not a separate model
Best for nothing — migrate.
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.