GroupDocs.Viewer MCP Server

MCP server that exposes GroupDocs.Viewer as AI-callable tools for Claude, Cursor, GitHub Copilot, and other MCP agents.

Installation

One-click installs pre-fill every supported setting: edit the placeholder documents folder after install (output defaults to the same folder); an empty GROUPDOCS_LICENSE_PATH runs in evaluation mode - point it at your license to lift limits.

More clients - ready-made configs for Claude Code, Codex CLI, Visual Studio 2022, Cursor, Windsurf, Cline, and JetBrains Rider live in install/generated/.

Requires .NET 10 SDK.

Run directly with dnx (recommended — no install step):

bash

dnx GroupDocs.Viewer.Mcp --yes

Pulls the latest stable release on every invocation. To pin to a specific version (recommended for shared configs and CI), append @<version>:

bash

dnx GroupDocs.Viewer.Mcp@26.9.0 --yes

Or install as a global dotnet tool:

bash

dotnet tool install -g GroupDocs.Viewer.Mcp
groupdocs-viewer-mcp

Or run via Docker:

Terminal

docker run --rm -i \
  -v $(pwd)/documents:/data \
  ghcr.io/groupdocs-viewer/viewer-net-mcp:latest

Native prerequisites

The underlying GroupDocs engine uses System.Drawing (GDI+) for some operations. When you run the server natively (via dnx or the global dotnet tool) on Linux or macOS, install the native libgdiplus library first:

Platform	Setup
Windows	Nothing — GDI+ is built into the OS.
Linux	`sudo apt-get install -y libgdiplus libfontconfig1 ttf-mscorefonts-installer`
macOS	`brew install mono-libgdiplus`
Docker	Nothing — the image already bundles `libgdiplus`.

Skipping this on Linux/macOS surfaces as DllNotFoundException: libgdiplus in the tool response. The simplest zero-setup option on Linux/macOS is the Docker image.

Available MCP Tools

Tool	Description
`RenderPage`	Renders a single document page as a PNG image and returns it inline (plus saves a copy to storage as `<source-stem>_page<N>.png`). Supports PDF, Word, Excel, PowerPoint, ODT, RTF, HTML, and 170+ more formats; optional `password` for protected documents.
`GetViewInfo`	Returns file type, page count, and per-page dimensions as JSON — without rendering. Useful as a pre-flight check before deciding which page(s) to render. Optional `password` for protected documents.

Example prompts for AI agents

Once the server is wired up to your MCP client (Claude Desktop, Cursor, VS Code Copilot, …), try:

Code

Render page 1 of report.pdf — show me the image.

How many pages does contract.docx have? What size is each page?

Show me page 5 of the slide deck quarterly.pptx.

Inspect /docs/legal-brief.pdf — what file type and page count?

Render the first three pages of presentation.pptx as PNGs.

The client picks RenderPage for "show me a page" requests and GetViewInfo for inspection-only questions.

Licensing

The MCP server itself is MIT; the underlying GroupDocs.Viewer engine requires a license for production use. Without one the server runs in evaluation mode:

Rendering processes a limited number of pages per document, and output may carry evaluation notices.
A single server process can open at most 15 documents; further calls fail with an evaluation-cap error until the server restarts.

There are two ways to license the server.

License file — point GROUPDOCS_LICENSE_PATH at your GroupDocs.Total.lic. Works offline.

Metered (pay-per-use) — set both GROUPDOCS_METERED_PUBLIC_KEY and GROUPDOCS_METERED_PRIVATE_KEY. You are billed for what you actually process, which suits AI agents well because their usage is bursty and hard to predict up front. If both a metered key pair and a license file are configured, metered wins and the file is ignored.

Metered mode needs outbound connectivity. Usage is reported to GroupDocs servers, so air-gapped or firewalled deployments must allow that egress — or use a license file instead.

Call the get_license_status tool at any time to see which mode is active, and — under metered — the consumed quantity and remaining credit.

Keeping the private key out of your config

The metered private key is a secret. MCP client configs are plain files on disk, and a project-scoped .mcp.json is committed by convention, so prefer, in order:

Set the variables in your OS environment and leave them out of the config entirely. An stdio MCP server inherits its client's environment, so this works in every client. On macOS note that an app launched from Finder does not inherit shell exports — use launchctl setenv, or launch the client from a terminal.
Reference them indirectly if your client supports it (Claude Code expands ${VAR}; VS Code uses ${env:VAR} and ${input:...}).
A literal value in a user-scoped config (for example ~/.claude.json) is acceptable for a single developer.
Never commit a literal key in a project-scoped .mcp.json.

For Docker, forward the values without writing them into any file:

Terminal

docker run --rm -i \
  -e GROUPDOCS_METERED_PUBLIC_KEY -e GROUPDOCS_METERED_PRIVATE_KEY \
  -v /path/to/documents:/data \
  ghcr.io/groupdocs-viewer/viewer-net-mcp:latest

To lift the limits with a license file:

Configuration

Variable	Description	Default
`GROUPDOCS_MCP_STORAGE_PATH`	Base folder for input and output files	current directory
`GROUPDOCS_MCP_OUTPUT_PATH`	(Optional) separate folder for output files	`GROUPDOCS_MCP_STORAGE_PATH`
`GROUPDOCS_LICENSE_PATH`	Path to GroupDocs license file	(evaluation mode)
`GROUPDOCS_METERED_PUBLIC_KEY`	Metered public key. Requires the private key too; takes precedence over the license file	(unset)
`GROUPDOCS_METERED_PRIVATE_KEY`	Metered private key. Secret - see Licensing	(unset)

Usage with Claude Desktop

config.json

{
  "mcpServers": {
    "groupdocs-viewer": {
      "type": "stdio",
      "command": "dnx",
      "args": ["GroupDocs.Viewer.Mcp", "--yes"],
      "env": {
        "GROUPDOCS_MCP_STORAGE_PATH": "/path/to/documents"
      }
    }
  }
}

To pin to a specific version, replace "GroupDocs.Viewer.Mcp" with "GroupDocs.Viewer.Mcp@26.9.0" in args. Pinning is recommended for shared / committed configs to avoid surprise upgrades.

Usage with VS Code / GitHub Copilot

NuGet.org generates a ready-to-use mcp.json snippet on the package page. Copy it directly into your .vscode/mcp.json.

Alternatively, add manually to .vscode/mcp.json:

config.json

{
  "inputs": [
    {
      "type": "promptString",
      "id": "storage_path",
      "description": "Base folder for input and output files.",
      "password": false
    }
  ],
  "servers": {
    "groupdocs-viewer": {
      "type": "stdio",
      "command": "dnx",
      "args": ["GroupDocs.Viewer.Mcp", "--yes"],
      "env": {
        "GROUPDOCS_MCP_STORAGE_PATH": "${input:storage_path}"
      }
    }
  }
}

Same pinning rule as above — swap "GroupDocs.Viewer.Mcp" for "GroupDocs.Viewer.Mcp@26.9.0" to lock to a specific release.

Usage with Docker Compose

bash

cd docker
docker compose up

Edit docker/docker-compose.yml to point volumes at your local documents folder.

Documentation & guides

Step-by-step deployment guides and a published-package integration test suite live in the companion repo GroupDocs.Viewer.Mcp.Tests:

Install from NuGet — dnx, global tool, pinned vs always-latest
Run via Docker
Verify on the MCP registry
Use with Claude Desktop
Use with VS Code / GitHub Copilot
Run the integration tests

That repo also exercises every advertised tool against the published NuGet artifact on Linux, macOS, and Windows in CI — so the snippets above are verified end-to-end on every release.

License

MIT — see LICENSE