Same tools and same engine as the hosted server at mcp.vithanco.com — the difference is where the work happens. The engine is compiled to WebAssembly, so a diagram is laid out and rendered locally, with no round trip and nothing to pay for.

npx @vithanco/vgraph-mcp

Claude Code, Claude Desktop, Cursor — anywhere an MCP server is configured by command:

{
  "mcpServers": {
    "vgraph": { "command": "npx", "args": ["-y", "@vithanco/vgraph-mcp"] }
  }
}

The hosted server remains the better fit where there is no shell to run a command in — claude.ai in the browser, ChatGPT connectors — and stays available:

{ "mcpServers": { "vgraph": { "url": "https://mcp.vithanco.com/mcp" } } }

What is in here

No graph logic. This is a host around the engine, the same way the Obsidian and VS Code plugins are — they put the wasm behind a pane, this one puts it behind a protocol on stdin.

file	what it does
`src/server.mjs`	MCP plumbing: list tools, dispatch, format the quality report
`src/wasm-host.mjs`	loads the wasm under WASI
`src/png.mjs`	rasterises the SVG
`tools.json`	tool definitions, generated from the Swift server
`vendor/`	the engine, its JS glue, and the fonts

tools.json is not written by hand. scripts/dump-mcp-tools.sh starts the native vgraph-mcp binary and asks it, over MCP, what tools it offers — so the VGL documentation the model reads has one source, in Swift, and a tool added there appears here without anyone editing JavaScript.

Building it

From the repository root:

just mcp-node       # build the wasm, vendor it with the fonts, refresh tools.json
just mcp-node-run   # run it on stdio against the current build

vendor/ is not committed. The wasm is 4.1MB, and a copy in git is a copy that can disagree with the engine it was built from.

Two things that look like bugs and are not

The wasm writes to stderr. It logs layout DEBUG lines to WASI stdout, and under a stdio MCP server stdout carries JSON-RPC. wasm-host.mjs routes both wasm fds to stderr; the noise is expected.

Fonts are bundled rather than read from the SVG. The SVG carries an @import for DM Sans, which browsers honour and rasterisers ignore — and resvg ignores an embedded @font-face too. See fonts/README.md at the repository root for why the faces are TTF and why there is one file per weight.