patch.js

#!/usr/bin/env node

/**
 * This script fixes the MCP SDK issue with pkce-challenge ES Module
 * It replaces the static require with a dynamic import in the auth.js file
 */

const fs = require("fs");
const path = require("path");

// Path to the file that needs patching
const authFilePath = path.resolve(
    __dirname,
    "node_modules",
    "@modelcontextprotocol",
    "sdk",
    "dist",
    "cjs",
    "client",
    "auth.js"
);

console.log("Checking if MCP SDK patch is needed...");

// Check if the file exists
if (!fs.existsSync(authFilePath)) {
    console.error(`Error: File not found at ${authFilePath}`);
    console.log(
        "Make sure you have installed @modelcontextprotocol/sdk package"
    );
    process.exit(1);
}

// Read the file content
const fileContent = fs.readFileSync(authFilePath, "utf8");

// Check if the file already contains our patch
if (fileContent.includes("loadPkceChallenge")) {
    console.log("MCP SDK is already patched!");
    process.exit(0);
}

// Check if the file contains the problematic require
if (!fileContent.includes('require("pkce-challenge")')) {
    console.log(
        "The MCP SDK file does not contain the expected require statement."
    );
    console.log("This patch may not be needed or the SDK has been updated.");
    process.exit(0);
}

console.log("Applying patch to MCP SDK...");

// The code to replace the problematic require
const requireLine =
    'const pkce_challenge_1 = __importDefault(require("pkce-challenge"));';
const replacementCode = `let pkce_challenge_1 = { default: null };
async function loadPkceChallenge() {
  if (!pkce_challenge_1.default) {
    const mod = await import("pkce-challenge");
    pkce_challenge_1.default = mod.default;
  }
}`;

// Replace the require line
let patchedContent = fileContent.replace(requireLine, replacementCode);

// Replace the function call to add the loading step
const challengeCall =
    "const challenge = await (0, pkce_challenge_1.default)();";
const replacementCall =
    "await loadPkceChallenge();\n    const challenge = await pkce_challenge_1.default();";
patchedContent = patchedContent.replace(challengeCall, replacementCall);

// Write the patched content back to the file
fs.writeFileSync(authFilePath, patchedContent, "utf8");

console.log("✅ MCP SDK patched successfully!");
console.log("The patch changes:");
console.log(
    "1. Replaced static require with dynamic import for pkce-challenge"
);
console.log("2. Added async loading function to handle the import");
console.log(
    "\nYou should now be able to run the application without ESM errors."
);