OpenSign Claude Integration

This repository contains the standalone Claude integration for OpenSign API v1.2. It exposes OpenSign e-signature operations as Claude tool definitions and provides execution helpers for calling the OpenSign API.

It also includes Claude Code plugin metadata and a bundled stdio MCP server so Claude can use the OpenSign tools directly after the plugin is installed and configured with an OpenSign API key.

The same MCP tools can be deployed as a remote MCP server on Cloudflare Workers. The Worker endpoint is /mcp and reads each user's OpenSign API key from a per-request bearer token.

Tools

• get_user: Get OpenSign account details.
• get_credits: Retrieve account credit details.
• create_contact: Add a new contact to the address book.
• create_draft_document: Generate a draft document with signer widgets.
• create_document: Create and send a document for signing.
• get_document: Retrieve a document by ID.
• get_document_list: List documents by status.

Claude Code plugin usage

The plugin manifest is in .claude-plugin/plugin.json. When the plugin is enabled, Claude Code prompts for:

• OpenSign API key
• OpenSign API base URL, defaulting to https://app.opensignlabs.com/api/v1.2

The API key is declared as a sensitive plugin option and is passed only to the bundled MCP subprocess.

The MCP server can be started manually for local validation:

OPENSIGN_API_KEY=<YOUR_OPENSIGN_API_KEY> npm run start:mcp

Cloudflare Workers remote MCP deployment

The Worker configuration is in wrangler.toml. It deploys worker.mjs as a stateless remote MCP server at /mcp.

The Worker does not store a shared OpenSign API key. MCP clients must send the end user's key on each request:

Authorization: Bearer <USER_OPENSIGN_API_KEY>

1. Install dependencies:

npm ci

2. Log in to Cloudflare:

npx wrangler login

3. Optionally override the API base URL if you are not using production:

npx wrangler secret put OPENSIGN_BASE_URL

If omitted, OPENSIGN_BASE_URL defaults to https://app.opensignlabs.com/api/v1.2 from wrangler.toml.

4. Validate the Worker bundle:

npm run check:worker

5. Deploy:

npm run deploy:worker

After deployment, the remote MCP URL will be:

https://opensign-claude-mcp.<YOUR_CLOUDFLARE_SUBDOMAIN>.workers.dev/mcp

For local Worker testing, create a local .dev.vars file that is not committed:

OPENSIGN_BASE_URL=https://app.opensignlabs.com/api/v1.2

Then run:

npm run dev:worker

Then call the MCP endpoint with the test user's key as a bearer token.

SDK usage

const OpenSignClaudeIntegration = require('./index');

const openSign = new OpenSignClaudeIntegration('<YOUR_OPENSIGN_API_KEY>');
const tools = openSign.getTools();

Pass tools to Claude when sending a request through the Anthropic SDK. When Claude returns a tool_use, call executeTool(toolUse.name, toolUse.input) and return the result to Claude as a tool_result.

Tests

npm ci
npm test
npm run check:worker