Fable 5 Outperforms Opus 4.8 in Cost and Efficiency Metrics

Fable 5 achieves a score of 60.8 on the FrontierCode 1.1 evaluation framework, surpassing Opus 4.8's score of 55.4. Fable 5 costs $1.86 when paired with its Sidekick, while Opus 4.8 with Sidekick costs $2.04, marking a 54% cost reduction compared to using Fable alone. In terms of efficiency, Fable + Sidekick leads to 11.5 turns per run, significantly lower than Opus + Sidekick's 26.5 turns per run. Fable 5 has been tested in 3,000 evaluation sessions, revealing that 81% of Fable-led runs required no code edits, compared to only 24% for Opus-led runs. Additionally, Fable's sidekick costs $0.58 per run, which is $0.27 more than Opus's sidekick cost of $0.31. The performance of Fable is influenced by its delegation strategy, which may not be effective for all tasks, particularly those lacking delegable components.