toolknit-mcp

MCP server that converts file formats by driving toolknit.com tool pages in headless Microsoft Edge.

All conversion work runs inside the page (client-side JS/WebAssembly — PDF.js, docx-preview, JSZip, canvas codecs), so files never leave the machine. The server only automates the page: set the file input → click convert → capture the download.

Tools exposed

Supported conversions (first version):

• word-to-pdf (docx → pdf), pdf-to-word, image-to-pdf (multi-file)

• pdf-to-image with options format (png/jpg/webp) and resolution (72/150/300)

• merge-pdf (multi-file), compress-pdf

• jpg-to-png, png-to-jpg, jpg-to-webp, png-to-webp, webp-to-jpg, webp-to-png, heic-to-jpg

Multi-image results arrive as ZIP and are auto-extracted next to the download (<name>_files/); the result JSON lists both the ZIP and the extracted files.

Related MCP server: document-converter-mcp

Example call

{
  "tool": "pdf-to-image",
  "input": "D:\\docs\\report.pdf",
  "options": { "format": "png", "resolution": "150" }
}

Requirements

• Node.js ≥ 18

• Microsoft Edge (uses the system install via playwright-core; no browser download)

Run / test

npm install
npm start          # stdio MCP server
npm test           # direct conversion smoke test (docx → pdf)
npm run test:mcp   # full MCP protocol end-to-end test

Register in an MCP client (stdio)

Clone, install, and point your MCP client at the server entry:

git clone https://github.com/Dawn-1029/toolknit-mcp.git
cd toolknit-mcp
npm install

{
  "mcpServers": {
    "toolknit": {
      "command": "node",
      "args": ["/path/to/toolknit-mcp/index.js"]
    }
  }
}

Windows example: "args": ["D:\\tools\\toolknit-mcp\\index.js"].

License

MIT

Implementation notes

• Tool pages share #file-input but use two button naming styles (#btn-convert/#convert-btn/#merge-btn/#compress-btn); each registry entry declares its selectors.

• Some pages import their tool script only after an async dependency chain (pdf-to-image waits for PDF.js), and Edge's injected change event is not always delivered — the driver re-dispatches change until the page's ready signal appears.

• Some pages raise blocking dialogs: merge-pdf opens a merge-all-pages modal for multi-page inputs, image-to-pdf offers image optimization mid-flow. Registry dismiss lists are clicked automatically (never the cancel variants).

• Download controls no-op until the page's result blob exists, so the driver clicks the download control on a 1.5s cadence until the browser fires the download event. image-to-pdf builds its download anchor dynamically (#download-buttons a[download]).

• Output never overwrites an input: merge tools name the result after the first input, so collisions are auto-renamed (smoke.pdf → smoke-1.pdf).

• pdf-to-word latency varies from ~25s to several minutes (site-side); its default timeout is 420s. All other tools finish in under ~15s for typical files.

• On failure the server saves a debug screenshot to the OS temp dir and includes its path plus any page errors in the error message.

• Site UI changes will break selectors; the fix is usually a one-line registry update in lib/converter.js.