Running GroupDocs MCP servers on-premise: architecture and security model Leave feedback

Run document comparison for AI agents fully on-premise: the GroupDocs.Comparison MCP server uses local stdio transport with no external endpoints, no inbound ports, and no telemetry — suitable for regulated environments where documents cannot leave the network. This page is the one to send your security reviewer.

Note

The commands and config snippets on this page are for the .NET build of the server — the only platform available today. Installation and client setup: MCP server for .NET. Other platforms will expose the same tools with their own launch command; everything else on this page applies unchanged.

+--------------+          +--------------------+         +------------------+
|  AI client   |  stdio   | MCP server process | reads / | local filesystem |
| (Claude, VS  | <----->  | (GroupDocs engine) | <-----> | storage / output |
| Code, agent) | JSON-RPC |   child process    |  writes |     folders      |
+--------------+          +--------------------+         +------------------+

• Transport: the AI client starts the server as a child process and communicates over standard input/output. The server never listens on a network socket — there is nothing to firewall, nothing to expose.
• Data path: agent → local server → local filesystem. Documents are read from and written to the folders you configure; no document content is transmitted anywhere.
• Network use: only at install time (pulling the package from nuget.org or the image from ghcr.io/docker.io). At runtime the server makes no outbound calls. In an air-gapped segment, pre-pull the image or pre-cache the package and pin the version.
• Telemetry: none. The server does not phone home, and the engine processes documents in-process.

Note the distinction that matters for review: the documents stay local unconditionally. The prompts go wherever your AI client’s model runs — with a cloud-hosted assistant, your instruction text (“compare contract-v1 with contract-v2”) reaches the model, as does any fragment the agent quotes back to you. Pair the server with a locally-hosted model and the entire loop stays inside the perimeter.

That last point deserves care in this product specifically: a comparison summary is document content. When an agent reports “the payment term changed from 30 to 45 days”, that sentence travels to the model provider like any other part of the conversation. If the changed text itself is sensitive, run a local model.

The Docker channel is usually the easier sell to a platform team: one image, pinned by digest, no SDK on the host.

docker run --rm -i \
  -v /srv/contracts:/data \
  -v /srv/licenses:/license:ro \
  -e GROUPDOCS_MCP_STORAGE_PATH=/data \
  -e GROUPDOCS_LICENSE_PATH=/license/GroupDocs.Comparison.lic \
  ghcr.io/groupdocs-comparison/comparison-net-mcp:26.9.1

• Pin the tag (:26.9.1, not :latest) so a rebuild cannot change behaviour underneath you.
• Mount the licence read-only; mount only the folders the agent should be able to reach.
• Images are multi-arch (linux/amd64 + linux/arm64) and carry every native dependency, which also removes the libgdiplus class of problem.

Two options, and the choice has a network consequence:

• License file — read from local disk by the local process. Works fully offline; the right answer for air-gapped deployments.
• Metered (pay-per-use) — reports usage to GroupDocs servers, so it needs outbound egress. Document content is never part of that report, but the connection itself must be allowed.

Both are covered in Licensing, including how to keep the metered private key out of committed config files.

A good fit: internal contract and proposal review, regulated industries (legal, financial, healthcare, public sector), air-gapped networks, and any team whose policy forbids uploading documents to third-party processors.

Not what this is: a multi-user service. One stdio server serves one client process on one machine. For a shared service you would put your own service in front of the GroupDocs library rather than running many MCP servers.

Does any document content leave the machine? No. Comparison happens in-process against local files.

Does it need internet at runtime? No — only to fetch the package or image at install time, and only when metered licensing is enabled.

Can I run it air-gapped? Yes. Pre-pull the image (or pre-cache the NuGet package), use a license file rather than metered keys, and pin the version.

What ports does it open? None. stdio only.

How do I prove that? Run it and watch: no listening sockets, no outbound connections during a comparison. The verification script performs a real handshake and a real engine call so you can observe exactly what happens.