ArcSync

arcsync-mcp

An MCP server that gives coding agents (Claude Code, Cursor, GitHub Copilot and other MCP clients) the architecture graph ArcSync parsed from your infrastructure-as-code: Terraform, AWS CDK, CloudFormation, Pulumi, Azure ARM and Serverless Framework.

Tools: list_diagrams, get_diagram (Mermaid or JSON, plus a canvas link), describe_resource, get_delta, list_versions, start_parse, get_parse_status. For diagrams the agent writes itself: validate_diagram (local check), push_diagram (store it and get canvas and Notion embed links), get_diagram_source, list_icons.

Setup

Add to .mcp.json (no credential in it, so it is safe to commit):

{
  "mcpServers": {
    "arcsync": {
      "command": "npx",
      "args": ["-y", "arcsync-mcp"]
    }
  }
}

Without Node.js

Each release also ships a standalone binary. On macOS or Linux, Homebrew installs it (on Intel Macs, Homebrew installs the npm package on its own Node.js instead):

brew install vanlandinghamlabs/tap/arcsync-mcp

On Windows, or without Homebrew, download the archive for your platform from Releases and check it with gh attestation verify <archive> -R VanLandinghamLabs/arcsync-mcp. Then use "command": "arcsync-mcp" with no args, and arcsync-mcp login / logout in place of the npx forms below.

The server is listed in the MCP Registry as io.github.VanLandinghamLabs/arcsync-mcp.

Connect

The first tool call returns a link to https://arcsync.dev/settings/mcp/connect. Open it, sign in, and click Connect: ArcSync mints an MCP credential and hands it to the server over 127.0.0.1, which saves it to ~/.config/arcsync/mcp-credential.json (mode 0600) and uses it from the next call. From a terminal, npx -y arcsync-mcp login does the same; npx -y arcsync-mcp logout deletes the saved file.

For CI or a shared machine, create an MCP credential at https://arcsync.dev/settings instead and pass ARCSYNC_CLIENT_ID and ARCSYNC_CLIENT_SECRET in the server's environment; they take precedence over a saved credential.

Two agent skills ship in skills/: arcsync-mcp tells an agent when to call each graph tool, and arcsync-diagrams teaches it to write, validate and push its own diagrams. For Claude Code, install both:

npm pack arcsync-mcp && tar -xzf arcsync-mcp-*.tgz package/skills
mkdir -p .claude/skills/arcsync-mcp .claude/skills/arcsync-diagrams
cp package/skills/arcsync-mcp/SKILL.md .claude/skills/arcsync-mcp/
cp package/skills/arcsync-diagrams/SKILL.md .claude/skills/arcsync-diagrams/
rm -rf package arcsync-mcp-*.tgz

Full guide: https://arcsync.dev/docs/mcp

Source and development

This repository is mirrored from the ArcSync monorepo on each release, together with the ArcSync core modules the server uses (vendor/core/). Releases are published to npm from here with provenance, so npm view arcsync-mcp --json links each version to the commit and workflow run that built it. Issues and pull requests are welcome; accepted changes are ported to the monorepo and ship in the next release.

npm ci
npm test
npm run build            # dist/index.js, one self-contained file
npm run eval:diagrams    # arcsync-diagrams skill evals; after build, costs model calls

License

MIT