Artificial Analysis Reruns VIALS-AA Without Tools: Tool Use Nearly Doubles Average Scores From ~25% to ~47%, and Claude Haiku 5.5 With Tools Beats Fable 5.2 Without Them at About a Tenth of the Cost
Independent evaluator Artificial Analysis reran VIALS-AA, its life-sciences visual reasoning benchmark, in a one-shot format with one request and no tools. Tool use lifted the cross-model average from about 25% to about 47%. Leader Claude Fable 5.2 (max) scores 67% with tools at $4.20 per task but 44% without them at $0.73, while Claude Haiku 5.5 (max) reaches 49% with tools at $0.07 per task. The same day AA also reported that across the Claude lineup, moving up a model tier usually beats maxing out effort on intelligence per dollar.

Key Takeaways
- Tools lift the VIALS-AA cross-model average from ~25% to ~47% (AA figures)
- Fable 5.2 (max): 67% at $4.20/task with tools vs 44% at $0.73 without, a 5.8x cost gap
- Haiku 5.5 (max) scores 49% at $0.07/task with tools; Opus 5.5 without tools scores only 34% at $0.33
- On 23 cell-counting tasks, Fable falls from 65% to 9% and Opus 5.5 (max) from 57% to 4% without tools
- Claude lineup: Opus 5.5 (xhigh, 57) beats Sonnet 5.5 (max, 55) at 40% lower cost per task and about half the time



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