Copperhead is an open-source AI agent that designs, documents, and verifies printed circuit boards using KiCad. Users describe changes or provide a product brief, and Copperhead edits real KiCad files, updates all referencing documents, and runs KiCad's own ERC and DRC checks until they pass. The system operates through an eight-stage gated pipeline: brief, spec, architecture, parts selection, schematic, layout, outputs, firmware, and dev plan. Each stage commits only when its gate verifies real work on disk, preventing drift — the core problem where design decisions spread across schematics, BOMs, power budgets, and documents fall out of sync. A respin caused by such inconsistency costs $5,000 to $50,000 and six to eight weeks.

Copperhead is proven on real hardware, demonstrated by the Open Telegraph pocket-size ESP32-S3 Morse key built end-to-end with this workflow. Every decision, check, and file is public. The CLI is free under Apache-2.0, runs locally with Node 20+, KiCad CLI, and a user-provided model API key (Claude or GPT-5). It works best iterating on existing KiCad repositories via `copperhead init`.

Paid tiers include Cloud ($49/user/month), Team ($49/user/month + $199/mo platform), and Enterprise (custom annual). Cloud adds hosted runs, web viewer with live schematic/board render, and managed inference credits. Team adds CI bot for PR checks, shared constraint libraries, SSO/SAML, and pooled credits. Enterprise offers self-hosted/VPC deployment, Altium support, RBAC, dedicated support, SLA, and audit trails.