Claude Fable 5.2 designs working hardware prototypes
Anthropic says Claude Fable 5.2 designed three electronic devices end to end, from schematics to firmware, and the prototypes worked without circuit fixes, suggesting models can now take on multi-step hardware design.
Anthropic reported that Claude Fable 5.2 designed three working electronic prototypes with minimal prompting: a speakerphone, a voice-assistant hub and a handheld virtual pet. The work was done with Diode Computers, a company that designs and manufactures circuit boards.
Each device started from a short prompt. For the speakerphone, the prompt asked for "a puck that plugs into a computer over USB-C and includes microphones and a speaker, supporting Bluetooth with a PCB antenna." Claude then wrote the specifications and drew schematics. It placed components and routed copper tracks on the printed circuit board, designed a 3D-printable enclosure, wrote the firmware and prepared a parts list. Diode's engineers assembled the boards under Claude's direction. Anthropic says none of the three devices needed changes to its circuitry, and all three still work after weeks of use.
Anthropic says the biggest gain over earlier models is geometric reasoning. On PCB Gym, an internal benchmark that Diode ran, Fable 5.2 scored 69% at placing components and routing connections, up from 25% for Fable 5. On the public BenchCAD 2.1 benchmark, which tests rebuilding 3D parts and boards from drawings, it scored 83.5%, nearly double Fable 5.1's score.
The company also says the model now revises its own work. Earlier models produced boards that were "95% complete but still unusable." Fable 5.2 reassigned pins, re-laid out sections of the board and repeatedly deleted and rerouted tracks when a design wasn't working.
There are limits. The devices are early prototypes. Anthropic says it does not yet know how they will hold up with continued use or whether they would pass commercial certification. The main layout result also comes from an internal benchmark.