idmly: HTML to InDesign (IDML) MCP server

idmly-mcp

Convert a self-contained HTML design into an editable Adobe InDesign file (.idml) from the AI agent you already use. This is the idmly engine exposed as a Model Context Protocol server, so Claude Code, Cursor, Codex, Windsurf or Claude Desktop can hand a finished design straight to InDesign.

The first two pages of any design convert free, no key needed. A $49 lifetime license unlocks unlimited full-document conversions and covers both the website and this tool.

Install

Node 20 or newer. The server runs with npx, nothing to clone. Start without a key and the free trial just works.

Claude Code

claude mcp add idmly -- npx -y idmly-mcp

Cursor, Windsurf, Claude Desktop (mcp.json / claudedesktopconfig.json)

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

Codex CLI (~/.codex/config.toml)

[mcp_servers.idmly]
command = "npx"
args = ["-y", "idmly-mcp"]

With a license, add the key from your purchase email as an environment variable:

claude mcp add idmly -e IDMLY_LICENSE_KEY=<your key> -- npx -y idmly-mcp

"env": { "IDMLY_LICENSE_KEY": "<your key>" }

env = { IDMLY_LICENSE_KEY = "<your key>" }

Tools

converttoindesign

Give it exactly one of:

Optional: out_dir (where to write; defaults to the source file's folder, or the current directory), name (output base name), platform (mac or win, which InDesign will open the file; picks glyph-fallback fonts, defaults to this machine).

It writes .idml and returns the path, pages converted, the fonts InDesign needs active, and a geometry check. A design with images comes back as a folder holding the .idml and a Links/ directory; keep them together and InDesign finds every image. Trial output is named -trial.idml.

idmly_status

Reports whether the engine is reachable and whether a license key is configured (presence only; the key is validated on the first conversion).

Writing HTML that converts well

• Each page is a fixed-size block with class page (or slide). A two-page reader spread is class spread. Typical sizes: 816×1056px Letter, 794×1123px A4, 1920×1080px slide, with overflow: hidden. A single fixed-width canvas with no markers converts as one page; a fluid width: 100% page has no intrinsic size.
• Keep the file self-contained: inline CSS and JS, fonts from Google Fonts or embedded, images as data URIs or absolute URLs. A stylesheet or image sitting next to the file is not uploaded.
• Draw charts as inline SVG or HTML rather than raster images, so they stay editable.
• Avoid scripts that never settle (a MutationObserver or resize handler that re-triggers itself). The engine renders the page once, measures it, and rebuilds it as InDesign frames.

Text becomes editable text frames with paragraph styles, tables stay tables, SVG and CSS shapes become vector objects.

Text a designer can keep editing

How the text is marked up decides how many frames it lands in and what the paragraph styles carry.

Shortened. The full README is on GitHub.