An Anthropic research post says Fable 5.2 produced three manufacturable circuit-board prototypes from one prompt, and scored 69% on partner Diode's internal layout grading, against 25% for Fable 5.

Concept illustration: a transparent display case outlined in black sits on a white base lettered ANTHROPIC, with a red inverted-V mark to the left of the lettering; inside, from left to right, stand an open laptop whose screen shows a speech bubble with three grey lines, a small black placard lettered FABLE 5.2, and three orange-red circuit boards upright on small white stands. The boards are drawn with dark chips and traces: the tall left one has a square of dots and a rectangular connector at its bottom edge, the wide middle one has a striped rectangle, and the tall right one has a white square near its top. Printed on the image: 3 Circuit-board prototypes, per Anthropic.

In Anthropic's account, Diode built three prototype circuit boards straight from Fable 5.2's design files, none of them yet through electrical validation or certification. Diode Computers designs and manufactures circuit boards for clients. The test strips a board's original layout, has the model place the components and route the connections again, and then Diode grades the result. The research post doesn't give the number of test items or the scoring method. The comparison is with Fable 5, not the previous Fable 5.1. The three devices are a USB-C speaker-microphone, a voice-assistant base and a handheld electronic pet. Diode manufactured them directly from the model's design files without any revisions, and Diode engineers assembled and tested them. The post says the devices still worked after several weeks of use. The post states that all three are prototypes, with no electrical validation, antenna tuning, thermal testing or certification. Anthropic has a commercial relationship with Diode and has used Diode tasks to train Claude on simple circuit work (Anthropic, 2026-11-09). Next to watch: whether a hardware team with no commercial tie reproduces the result. How we checked →

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This item ran in the brief of Nov 10, 2026, alongside 12 other items. How we checked it, the quote checks and what was still missing that day are on that issue's How we checked page.

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SecondSource (2026). "An Anthropic research post says Fable 5.2 produced three manufacturable circuit-board prototypes from one prompt, and scored 69% on partner Diode's internal layout grading, against 25% for Fable 5.." https://secondsource.io/en/research/2026-11-10-1/. Accessed access date.