Claude Fable 5.2 Tops VIALS-AA Scientific Visual Reasoning Benchmark
Artificial Analysis built VIALS-AA on Handshake AI's VIALS benchmark to test visual reasoning over life-science artifacts such as gel blots, plasmid maps and phylogenies. Claude Fable 5.2 leads at 67%, ahead of Gemini 4 Carbon (64%) and GPT-6 Astra (63%). The more notable signal is tool-use strategy: Fable averages roughly 37 tool calls per task with heavy batching, versus about 8 for Astra, suggesting reasoning models are shifting toward multi-step tool orchestration rather than single-shot answers.
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Artificial Analysis (@ArtificialAnlys) · 2026-11-10 03
Claude Fable 5.2 leads scientific visual reasoning benchmark VIALS-AA; it makes more tool calls than any other Anthropic model, unlike OpenAI models which make fewer as they get smarter
VIALS-AA is our implementation of @joinHandshakeAI’s VIALS benchmark for visual reasoning in life sciences research, across artifacts such as gel blots, plasmid maps, and phylogenies. Claude Fable 5.2 (max with fallback) scores 67% on VIALS-AA, ahead of Gemini 4 Carbon (high) at 64% and GPT-6 Astra (max) at 63%. Fable averages ~37 tool calls per task, while Astra averages ~8, the fewest of any model we’ve tested.
On turn 4 of this protein interaction task, Fable creates crops and asks to view them. On turn 10, it builds a color mask by thresholding color channels. On turn 17, it fits a circle to each arc and unrolls the arc into a straight strip. On turn 31, it counts the bars as peaks in an intensity profile. And on turn 41, it maps every detected spoke back on the original image to check its work. Fable batches calls on 28 of its 51 turns, averaging 1.75 tool calls per turn, compared with 1.12 for Sonnet 5.5.
