PCB

Zener is a Starlark-based HDL for PCB design. .zen files define components, nets, interfaces, and modules. Key concepts:

•Net: electrical connection between pins
•Component: physical part with symbol, footprint, pins
•Interface: reusable grouped connection pattern (e.g., Spi, I2c, Uart)
•Module: hierarchical subcircuit, instantiated with Module("path.zen")

IMPORTANT: Before writing or modifying .zen code, run pcb doc spec to read the language specification. The spec covers syntax, built-in functions, type system, and common patterns. For specific topics: pcb doc spec --list shows all sections, pcb doc spec/<section> reads one section.

Prefer stdlib generics (@stdlib/generics/) over specific components when possible. Generics like Resistor, Capacitor, Led are parameterized by value/package and resolved to real parts at build time.

Common imports: load("@stdlib/interfaces.zen", "Power", "Ground", "Spi", "I2c", ...) for standard net types and interfaces.

CLI Commands

bash

# scaffolding
pcb new --workspace <NAME>   # Create new workspace with git init
pcb new --board <NAME>       # Add board to existing workspace (boards/<NAME>/)
pcb new --package <PATH>     # Create package at path (modules, etc.)
pcb new --component          # Interactive TUI (use search_component + add_component MCP tools instead)

bash

pcb build [PATH]         # Build and validate (default: cwd)
pcb fmt [PATH]           # Format .zen files (default: cwd)
pcb bom <FILE> -f json   # Generate BOM as JSON with availability data
pcb fork add <URL>       # Fork dependency for local dev
pcb fork remove <URL>    # Remove fork

bash

# JavaScript scripting with MCP tools
pcb mcp eval 'tools.search_registry({query: "buck"})'  # Search registry
pcb mcp eval -f script.js                              # Run from file

Use pcb mcp eval to chain multiple tool calls. Tools available via tools.name({...}), metadata at tools._meta.

MCP Tools

Tool	Use
`search_registry`	Find modules/components in Zener registry (try FIRST). Returns pricing and availability data.
`search_component`	Search Diode online database (fallback). Returns pricing and availability data.
`add_component`	Download component to workspace

Documentation

bash

pcb doc spec               # Full language specification
pcb doc spec --list        # List all spec sections
pcb doc spec/<section>     # Read specific section (e.g., spec/io, spec/module)
pcb doc packages           # Dependency management docs

Package docs (stdlib, registry packages):

bash

pcb doc --package @stdlib                                           # Standard library docs
pcb doc --package @stdlib --list                                    # List files as tree
pcb doc --package @stdlib/generics                                  # Filter to subdirectory
pcb doc --package github.com/diodeinc/registry/module/<xyz>@0.1.0   # Remote package

Part Sourcing & BOM Matching

Generic components are matched to "house parts" (pre-qualified, good availability). Warnings like No house cap found for ... or No house resistor found for ... mean no house part matches the spec—adjust the spec or specify mpn + manufacturer to use a specific part.

pcb bom <FILE> -f json outputs sourcing data with availability_tier ("plenty" | "limited" | "insufficient") and distributor offers by region.