# Claude Fable 5.1 vs Claude Opus 5

Every finance benchmark where both have a score (Anthropic and Anthropic). Data refreshed 2 Nov 2026. Scores from different benchmarks use different scales and are not added up.

| Benchmark | Metric | Claude Fable 5.1 | Claude Fable 5.1 source | Claude Opus 5 | Claude Opus 5 source | Ahead |
| --- | --- | --- | --- | --- | --- | --- |
| MortgageTax | accuracy % (higher is better) | 70.8 | Vals.ai MortgageTax leaderboard, 1 Sept 2026, https://www.vals.ai/benchmarks/mortgage_tax | 72.1 | Vals.ai MortgageTax leaderboard, 1 Sept 2026, https://www.vals.ai/benchmarks/mortgage_tax | Claude Opus 5 |
| Tax Agent Bench | accuracy % (all-pass x citation factor) (higher is better) | 49.2 | Vals.ai leaderboard, 29 Oct 2026, https://www.vals.ai/benchmarks/tax_agent_bench | 45.5 | Vals.ai leaderboard, 29 Oct 2026, https://www.vals.ai/benchmarks/tax_agent_bench | Claude Fable 5.1 |

Source: https://benchmarks.finance/compare/claude-fable-5-1-vs-claude-opus-5/

Created and maintained by Moneda.