A zero-configuration linter for Verilog, SystemVerilog, and VHDL that validates what your AI agents write. Runs in Claude and Codex through MCP. By Sigasi.

This beta release is free to test until the full release in a few weeks time.

What Magic HDL does

Catches what agents get wrong. AI-generated HDL can look right and still be wrong. Every diagnostic carries a rule ID you can trace.
Fewer tokens spent on fixes. Letting the agent hunt its own mistakes costs tokens on every attempt. Magic HDL names the problem the first time, so you pay for less rework.
Zero configuration. Point it at your code and it works. No rule files, no project setup.
Built into your agent's loop. An MCP server lets Claude and Codex check its own work as it writes.

Installation for your AI agent

Magic HDL ships an MCP server: a small program your agent can talk to, to let it check its own HDL while it writes, instead of waiting for you to run anything. Setting it up asks for a license key, once per device. Create a key, or find one you already have, in your account.

An entry that is already there is kept; pass --force to replace it. Start a new session with your AI agent to reload the configuration. Go ahead and ask it about a Verilog, SystemVerilog, or VHDL file or project.

Claude Code

In Claude Code, one command sets it up:

npx @sigasi/magic-hdl setup

This registers Magic HDL with Claude Code as an MCP server named magic-hdl, for every project on this machine.

Claude Desktop

Claude Desktop has no command line to configure an MCP server. Instead, add the name of that app to the same command, and it prints the required claude_desktop_config.json for this platform to paste it into:

npx @sigasi/magic-hdl setup claude-desktop

The same entry is printed whenever the registration itself cannot be made. For example, when claude isn't on the PATH.

Codex

Codex has its own command line:

npx @sigasi/magic-hdl setup codex

This adds a magic-hdl MCP server to ~/.codex/config.toml, for every Codex session on this machine.

Codex

Codex has a command line of its own, so one command registers Magic HDL there too:

npx @sigasi/magic-hdl setup codex

This adds a magic-hdl MCP server to ~/.codex/config.toml, for every Codex session on this machine. An entry that is already there is kept — pass --force to replace it. Start a new Codex session afterwards.

Any other agent that speaks MCP

The same command and arguments work anywhere. Most agents keep those in a configuration file:

{
  "mcpServers": {
    "magic-hdl": {
      "command": "npx",
      "args": ["-y", "@sigasi/magic-hdl", "serve"]
    }
  }
}

Logging in without setting anything up

npx @sigasi/magic-hdl login

Stores a license token for this machine without registering the server with any agent.

Removing it again

Claude Code and Codex own the configuration of the server, so you remove it using their own commands:

claude mcp remove -s user magic-hdl
codex mcp remove magic-hdl

Usage

npx @sigasi/magic-hdl --help

See CHANGELOG.md for recent changes.

What gets installed

Magic HDL ships with a specific runtime per operating system. The runtime matching your platform is installed automatically as an optional dependency (Linux, macOS arm64, or Windows). Node 18 or newer.