On 9 November, as it launched its new model Claude Fable 5.2, Anthropic described an experiment in which the model designed electronic devices from prompt to prototype. Its partner was Diode Computers, which designs and manufactures circuit boards and has a commercial relationship with Anthropic.

The devices were a speakerphone that connects to a computer over USB-C, a home voice-assistant hub and a battery-powered virtual pet. For the speakerphone, the model received only a short description: microphones, a speaker and Bluetooth with an antenna on the circuit board. The model wrote the specifications, drew the schematics, placed the components on a four-layer board and routed the copper traces between them. It also designed a 3D-printable enclosure, wrote the firmware and compiled the bill of materials.

Diode manufactured the boards directly from the model’s files without any revision rounds, and its engineers assembled and tested the devices following the model’s instructions. Anthropic said all three worked without changes to the circuits and are still in working order, the speakerphone even after weeks of use. Diode steered the model mainly with short directives such as ‘clean up the schematic’ and ‘continue’.

The result does not show whether the devices would be viable as products. They are prototypes that have had no electrical validation, antenna tuning, thermal testing or certification, and they were not designed for mass production. The company does not know how they will hold up under continuous use. The model had no access to measuring instruments or manufacturing machines, so people did the physical work.

How it differs from earlier models

Anthropic said the biggest change was in geometric reasoning: placing components and routing traces. Earlier models placed supporting components too far from the circuits and rarely corrected their own work. Over the past year, Diode used them to produce many boards that were 95 per cent complete but unusable.

Fable 5.2 routed high-speed signals, high currents and noise-sensitive connections first. When the voice-assistant hub’s traces became tangled, it unpicked and rerouted them dozens of times. For long traces, it wrote its own routing program, which routed a trace in about a second.

Benchmark results

In Diode’s internal PCB Gym benchmark, the model places components and routes connections on boards whose original layout has been removed. Fable 5.2 scored 69 per cent and Fable 5 25 per cent. In the public BenchCAD 2.1 benchmark, the model builds 3D parts, assemblies and circuit boards from drawings and images; scores run from 0 to 100, with partial credit. At the highest reasoning effort, Fable 5.2 scored 83.5 points, Opus 5.5 65.3 and Fable 5.1 44.4.

The figures come from Anthropic and its partner. The New Stack and The Verge reported the company’s data but did not test it themselves.

Fable 5.2 is available on all platforms, and its API price is $8 per million input tokens and $40 per million output tokens. For most coding and knowledge-work tasks, the company still recommends Opus 5.5.