Design circuit boards as code.

Turn text-based circuit designs into KiCad schematics, PCB layouts, and bills of materials.

Open source. Built for engineers and AI agents.

Quick Start · Features · Examples · Documentation · Contributing

Introduction

Synth is an open-source compiler for electronic circuit boards. Describe your components, their connections, and board constraints in SynthSpec, a text-based design language. Synth checks the design and generates KiCad schematics, PCB layouts, and a bill of materials.

This brings a software development workflow to hardware: edit designs in your usual editor, review changes in Git, and run automated checks. Your .synth files capture the design intent; the schematic and board layout are generated outputs you can inspect in KiCad.

Engineers can use Synth from the command line. AI agents can use its Model Context Protocol (MCP) server to find components, validate circuits, and generate outputs through the same compiler, with structured diagnostics to guide corrections.

Why Synth?

• Review hardware changes in Git. Components, connections, and constraints are text, making design intent visible in diffs and pull requests.
• Check designs as you build. Structured diagnostics identify problems and provide source locations and suggested fixes where available.
• Keep outputs reproducible. A typed compiler pipeline and deterministic placement and routing make generated artifacts repeatable.
• Work with KiCad. Export schematics, PCBs, and BOMs for inspection and downstream workflows.
• Give agents concrete tools. Expose validation, registry search, placement, routing, and export through MCP.

How It Works

flowchart LR
    source["SynthSpec source"] --> compiler["Parse & resolve"]
    compiler --> checks["Validate"]
    checks --> layout["Place & route"]
    layout --> export["KiCad project & BOM"]
    checks --> feedback["Diagnostics & fixes"]
    feedback --> source

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Synth resolves parts from a component registry and lowers the source into a typed board representation. Compiler stages use that shared representation for electrical checks, layout, routing, and export. A local browser viewer displays the schematic and diagnostics as you edit.

Features

Area	Capabilities
Design language	SynthSpec parser, typed board IR, components, connections, differential pairs, keepouts, and placement hints
Validation	Electrical-rule checks, design-rule checks, structured diagnostics, and SMT-backed quantitative fixes
Layout and routing	Deterministic schematic layout, component placement, and multilayer routing
KiCad integration	Project, schematic, PCB, and BOM export; optional fabrication outputs through kicad-cli
Component registry	Versioned parts, project and user overlays, search, import, and authoring tools
Developer tools	CLI, live browser preview, JSON diagnostics, and an MCP server for agent integration

Quick Start

Use a current stable Rust toolchain with Cargo. Run the following from a local checkout:

git clone https://github.com/absmach/synth.git
cd synth
cargo build -p synth-cli
cargo run -p synth-cli -- --help

Validate the minimal example and export a KiCad project:

cargo run -p synth-cli -- validate fixtures/designs/hello.synth
cargo run -p synth-cli -- export-kicad fixtures/designs/hello.synth --out output/hello

The minimal example declares an empty two-layer board. Use the example designs to explore circuits with components and connections.

For machine-readable diagnostics:

cargo run -p synth-cli -- validate examples/env_logger.synth --format json

Open exported projects in KiCad. Optional Gerber, drill, and STEP exports require kicad-cli; see the KiCad workflow guide for export and review details.

Live Preview

Build the browser assets using the prerequisites and instructions in the viewer guide, then run:

cargo run -p synth-cli -- preview examples/env_logger.synth

Open the local URL printed by the command. Save changes to the .synth file in your editor to refresh the schematic and diagnostics.

Agent Integration

Start the MCP server over standard input and output:

cargo run -p synth-cli -- mcp --stdio

Agents can retrieve the SynthSpec language reference, search the registry, validate designs, apply fixes, and invoke compiler stages. See the MCP guide for transports and tool details.

Examples

Design	What it demonstrates
Hello	The smallest board declaration
Environmental logger	USB-C power, a regulator, an MCU, an environmental sensor, and a debug header
Sensor logger	A larger design with dual I²C sensors, SPI flash, and status LEDs
Placement and differential pairs	Placement hints, differential-pair constraints, and keepout regions

Additional language and validation cases live in fixtures. Part definitions live in the component registry.

Documentation

• KiCad workflows — exported projects, validation, BOMs, and fabrication outputs.
• Schematic procedures — schematic generation and review.
• Diagnostic reference — diagnostic codes and repair guidance.
• Diagnostic protocol — the machine-readable diagnostic format.
• Component registry — part definitions and registry structure.
• Browser viewer — build and run the live preview.
• MCP server — agent tools and integration.

Contributing

Contributions to the compiler, component registry, examples, and documentation are welcome. Use issues to report bugs or discuss a change, and submit a pull request with a focused description and relevant validation.

Before submitting code, run the workspace checks:

make verify

This checks formatting, compilation, Clippy lints, the workspace tests, and registry tests. Run make help to see individual development commands.

License

Synth is licensed under the Apache License 2.0.