MCP Server

MCP Server for AI Agents

Send documents for e-signature from Claude Desktop, Cursor, and other MCP-compatible AI tools — using natural language.

What is MCP?

The Model Context Protocol (MCP) is an open standard that lets AI assistants like Claude use external tools. SignForge's MCP server gives Claude the ability to create envelopes, send documents for signing, check status, and download signed PDFs — all through conversation.

Example conversation

You: “Send the NDA at ~/Documents/nda.pdf to jane@acme.com for signing”

Claude: “Done! I've created envelope #abc123 and sent it to jane@acme.com. She'll receive an email with a signing link.”

You: “Has she signed it yet?”

Claude: “Not yet — Jane viewed the document 10 minutes ago but hasn't signed. Status: viewed.”

Installation

Get your API key

Go to Dashboard → Developers and create an API key. Use a test key for experimenting.

Configure Claude Desktop

Add this to your Claude Desktop config file:

macOS

~/Library/Application Support/Claude/claude_desktop_config.json

Windows

%APPDATA%\Claude\claude_desktop_config.json

json

{
  "mcpServers": {
    "signforge": {
      "command": "npx",
      "args": ["-y", "@signforge/mcp-server"],
      "env": {
        "SIGNFORGE_API_KEY": "sf_live_YOUR_KEY"
      }
    }
  }
}

Restart Claude Desktop

Quit and reopen Claude Desktop. You should see a hammer icon indicating MCP tools are connected.

Available Tools

The MCP server exposes 4 tools that Claude can use automatically based on your requests:

create_and_send

Create an envelope with a PDF, add a signer, and send for e-signature.

Params: title, signer_email, signer_name, pdf_path or pdf_base64

check_status

Check the current status of an envelope including recipient signing status.

Params: envelope_id

list_envelopes

List your envelopes with optional status filter.

Params: status (optional), limit (optional)

download_signed

Download the signed PDF for a completed envelope to a local file.

Params: envelope_id, output_path

Environment Variables

Variable	Required	Description
SIGNFORGE_API_KEY	Required	Your SignForge API key (live or test)
SIGNFORGE_API_URL	Optional	API base URL (default: `https://signforge.io/api/v1`)

Other MCP Clients

The SignForge MCP server works with any MCP-compatible client. Here are configs for popular tools:

Claude Code (CLI)

json

// In your project's .mcp.json:
{
  "mcpServers": {
    "signforge": {
      "command": "npx",
      "args": ["-y", "@signforge/mcp-server"],
      "env": {
        "SIGNFORGE_API_KEY": "sf_live_YOUR_KEY"
      }
    }
  }
}

Run directly with npx

bash

SIGNFORGE_API_KEY=sf_live_YOUR_KEY npx -y @signforge/mcp-server

The server communicates over stdio, so it integrates with any MCP transport that supports the stdio protocol.

Troubleshooting

Claude doesn't show the hammer icon

Make sure you saved the config file and fully restarted Claude Desktop (Cmd+Q, not just close window). Check that Node.js 18+ is installed.

"SIGNFORGE_API_KEY environment variable is required" error

Your API key isn't reaching the server. Check the "env" block in your config — the key must be in the env object, not as a command-line argument.

"SignForge API error (401)" on tool calls

Your API key is invalid or revoked. Go to Dashboard → Developers and verify the key is active. Generate a new one if needed.

"SignForge API error (429)" rate limit

You've exceeded the rate limit (60 requests/min). Wait a moment and try again. Sandbox mode has a higher rate limit.