#!/usr/bin/env node
/**
* Superlines MCP Proxy
*
* A lightweight proxy script that connects Claude Desktop (or other MCP clients)
* to the Superlines MCP server. This script handles the stdio transport and
* forwards requests to the remote Superlines API.
*
* Usage:
* 1. Save this file locally (e.g., ~/superlines-mcp/mcp-proxy.js)
* 2. Configure Claude Desktop to use it (see README.md)
* 3. Set SUPERLINES_API_KEY environment variable
*
* @see https://github.com/Superlines/mcp-server
* @see https://superlines.io/integrations/mcp
*/
const https = require('https');
const readline = require('readline');
// Configuration
const MCP_SERVER_URL = process.env.MCP_SERVER_URL || 'https://mcp.superlines.io';
const API_KEY = process.env.SUPERLINES_API_KEY;
// Validate API key
if (!API_KEY) {
console.error(JSON.stringify({
jsonrpc: '2.0',
error: {
code: -32600,
message: 'SUPERLINES_API_KEY environment variable not set. Get your API key at https://analytics.superlines.io/settings/api-keys'
},
id: null
}));
process.exit(1);
}
// Create readline interface for stdin/stdout
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
terminal: false
});
// Handle incoming JSON-RPC messages
rl.on('line', async (line) => {
try {
const message = JSON.parse(line);
// Check if this is a notification (no id field)
const isNotification = !('id' in message) || message.id === undefined;
// Forward request to remote MCP server
const data = JSON.stringify(message);
const url = new URL(MCP_SERVER_URL);
const options = {
hostname: url.hostname,
port: 443,
path: url.pathname,
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Content-Length': Buffer.byteLength(data),
'Authorization': `Bearer ${API_KEY}`
},
timeout: 90000 // 90 seconds to handle cold starts
};
const req = https.request(options, (res) => {
let responseData = '';
res.on('data', (chunk) => {
responseData += chunk;
});
res.on('end', () => {
// For notifications, don't send a response
if (isNotification) return;
try {
const parsed = JSON.parse(responseData);
// Ensure required JSON-RPC fields
if (!parsed.jsonrpc) parsed.jsonrpc = '2.0';
if (parsed.error && !parsed.id && message.id) parsed.id = message.id;
console.log(JSON.stringify(parsed));
} catch (error) {
console.log(JSON.stringify({
jsonrpc: '2.0',
id: message.id || null,
error: {
code: -32603,
message: 'Failed to parse server response'
}
}));
}
});
});
req.on('error', (error) => {
console.log(JSON.stringify({
jsonrpc: '2.0',
id: message.id,
error: {
code: -32603,
message: `Connection error: ${error.message}`
}
}));
});
req.on('timeout', () => {
req.destroy();
console.log(JSON.stringify({
jsonrpc: '2.0',
id: message.id,
error: {
code: -32603,
message: 'Request timeout - server may be experiencing cold start. Please retry.'
}
}));
});
req.write(data);
req.end();
} catch (error) {
console.log(JSON.stringify({
jsonrpc: '2.0',
error: { code: -32700, message: 'Parse error' },
id: null
}));
}
});
// Handle uncaught exceptions gracefully
process.on('uncaughtException', (error) => {
console.log(JSON.stringify({
jsonrpc: '2.0',
error: {
code: -32603,
message: `Internal error: ${error.message}`
},
id: null
}));
});
// Handle stdin close
rl.on('close', () => {
process.exit(0);
});
