GroupDocs.Signature MCP Server

MCP server that exposes GroupDocs.Signature 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):

dnx GroupDocs.Signature.Mcp --yes

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

dnx GroupDocs.Signature.Mcp@26.9.0 --yes

Or install as a global dotnet tool:

dotnet tool install -g GroupDocs.Signature.Mcp
groupdocs-signature-mcp

Or run via Docker:

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

Native prerequisites

The underlying GroupDocs engine renders signature glyphs (text, QR codes, barcodes) onto document pages via System.Drawing (GDI+). When you run the server natively (via dnx or the global dotnet tool) on Linux or macOS, install the native libgdiplus library and a fonts package first:

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

Example prompts

• "Sign contract.pdf with a QR code containing 'Signed by Alice'"
• "Verify all signatures in agreement.docx and tell me if any failed"
• "Search invoice.pdf for QR codes — return the decoded text and the QR images"
• "Are there any digital signatures in this report.pdf? If so, who signed it?"
• "Add a text signature 'APPROVED' to the bottom-right of every page of policy.pdf"

Licensing

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

• Operations run with evaluation limits, 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:

1. 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.
2. Reference them indirectly if your client supports it (Claude Code expands ${VAR}; VS Code uses ${env:VAR} and ${input:...}).
3. A literal value in a user-scoped config (for example ~/.claude.json) is acceptable for a single developer.
4. Never commit a literal key in a project-scoped .mcp.json.

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

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

To lift the limits with a license file:

• Get a free 30-day temporary license
• Purchase a license | Product page

Configuration

Usage with Claude Desktop

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

To pin to a specific version, replace "GroupDocs.Signature.Mcp" with "GroupDocs.Signature.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:

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

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

Usage with Docker Compose

cd docker
docker compose up

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

License

MIT — see LICENSE