feat: add OAuth 2.1 authentication via Scalekit for HTTP transport

.env.example

@@ -0,0 +1,29 @@
+# ─── Meta Ads ────────────────────────────────────────────────────────────────
+# Required: Meta (Facebook) User Access Token with ads_read permission
+META_ADS_ACCESS_TOKEN=your_meta_access_token_here
+
+# ─── Transport ────────────────────────────────────────────────────────────────
+# "stdio" (default) or "http"
+TRANSPORT=http
+PORT=3000
+
+# ─── Scalekit OAuth 2.1 ──────────────────────────────────────────────────────
+# Set OAUTH_ENABLED=true to require valid Scalekit JWT on all /mcp requests.
+# Leave unset or set to false for local dev / stdio mode.
+OAUTH_ENABLED=true
+
+# From Scalekit dashboard → API Credentials
+SCALEKIT_ENVIRONMENT_URL=https://<your-env>.scalekit.cloud
+SCALEKIT_CLIENT_ID=skc_...
+SCALEKIT_CLIENT_SECRET=sks_...
+
+# Your MCP server's public URL (used as OAuth resource identifier + audience claim).
+# Must match the "Server URL" configured in Scalekit dashboard → MCP Servers.
+MCP_SERVER_URL=https://mcp.yourapp.com
+
+# Autogenerated resource ID from Scalekit dashboard (only needed if MCP_SERVER_URL is NOT set).
+# SCALEKIT_RESOURCE_ID=res_...
+
+# Comma-separated list of OAuth scopes your server advertises.
+# These must match the scopes defined in Scalekit dashboard → MCP Servers → Scopes.
+MCP_SCOPES=meta_ads:read

README.md

@@ -79,6 +79,62 @@ TRANSPORT=http META_ADS_ACCESS_TOKEN=YOUR_META_ACCESS_TOKEN PORT=8080 node dist/
 Endpoints:
 - `POST /mcp` — MCP protocol endpoint (use this as your connector URL)
 - `GET /health` — Health check (`{"status":"ok"}`)
+- `GET /.well-known/oauth-protected-resource` — OAuth 2.1 discovery (RFC 9728)
+
+## OAuth 2.1 Authentication (Scalekit)
+
+For production deployments, secure the HTTP server with [Scalekit](https://scalekit.com) OAuth 2.1. This enables Claude Desktop, Cursor, VS Code, and any MCP-compliant client to authenticate users via social login or enterprise SSO before accessing your tools.
+
+### Setup
+
+1. Create a free [Scalekit account](https://app.scalekit.com/ws/signup)
+2. In the dashboard → **MCP Servers** → **Add MCP server**:
+   - Enable **Dynamic Client Registration** and **CIMD**
+   - Add scopes (e.g., `meta_ads:read`)
+   - Set **Server URL** to your public MCP server URL
+3. Copy credentials to your environment:
+
+```bash
+TRANSPORT=http \
+OAUTH_ENABLED=true \
+SCALEKIT_ENVIRONMENT_URL=https://<env>.scalekit.cloud \
+SCALEKIT_CLIENT_ID=skc_... \
+SCALEKIT_CLIENT_SECRET=sks_... \
+MCP_SERVER_URL=https://mcp.yourapp.com \
+MCP_SCOPES=meta_ads:read \
+META_ADS_ACCESS_TOKEN=YOUR_META_ACCESS_TOKEN \
+node dist/index.js
+```
+
+Copy `.env.example` to `.env` and fill in your values, then run with `node -r dotenv/config dist/index.js`.
+
+### Environment Variables
+
+| Variable | Required | Description |
+|----------|----------|-------------|
+| `OAUTH_ENABLED` | No | Set `true` to enable JWT validation on all `/mcp` requests |
+| `SCALEKIT_ENVIRONMENT_URL` | When OAuth enabled | Your Scalekit environment URL |
+| `SCALEKIT_CLIENT_ID` | When OAuth enabled | Scalekit client ID |
+| `SCALEKIT_CLIENT_SECRET` | When OAuth enabled | Scalekit client secret |
+| `MCP_SERVER_URL` | Recommended | Public URL of this server (used as OAuth audience) |
+| `SCALEKIT_RESOURCE_ID` | Fallback | Autogenerated resource ID if `MCP_SERVER_URL` is not set |
+| `MCP_SCOPES` | No | Comma-separated advertised scopes (default: `meta_ads:read`) |
+
+### How it works
+
+```
+MCP Client (Claude/Cursor)
+  │
+  ├─ GET /.well-known/oauth-protected-resource  ← discovers Scalekit as auth server
+  │
+  ├─ OAuth flow via Scalekit (PKCE + DCR/CIMD)
+  │   └─ Returns short-lived JWT (300–3600s)
+  │
+  └─ POST /mcp  Authorization: Bearer <jwt>     ← validated by authMiddleware
+       └─ scalekit.validateToken(jwt, { audience })
+```
+
+OAuth is **opt-in**: without `OAUTH_ENABLED=true` the server runs unauthenticated (suitable for local stdio use).
 
 ### Claude.ai Custom Connector
 

package.json

@@ -24,6 +24,7 @@
   },
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.6.1",
+    "@scalekit-sdk/node": "^2.3.0",
     "axios": "^1.7.9",
     "express": "^5.2.1",
     "zod": "^3.23.8"

src/auth/scalekit.ts

@@ -0,0 +1,160 @@
+import { Scalekit } from "@scalekit-sdk/node";
+import type { NextFunction, Request, Response } from "express";
+
+// ---------------------------------------------------------------------------
+// Scalekit client (lazy-initialized so stdio mode never touches these vars)
+// ---------------------------------------------------------------------------
+
+let _scalekit: Scalekit | null = null;
+
+function getScalekitClient(): Scalekit {
+  if (_scalekit) return _scalekit;
+
+  const envUrl = process.env.SCALEKIT_ENVIRONMENT_URL;
+  const clientId = process.env.SCALEKIT_CLIENT_ID;
+  const clientSecret = process.env.SCALEKIT_CLIENT_SECRET;
+
+  if (!envUrl || !clientId || !clientSecret) {
+    throw new Error(
+      "OAuth is enabled but Scalekit credentials are missing. " +
+        "Set SCALEKIT_ENVIRONMENT_URL, SCALEKIT_CLIENT_ID, and SCALEKIT_CLIENT_SECRET."
+    );
+  }
+
+  _scalekit = new Scalekit(envUrl, clientId, clientSecret);
+  return _scalekit;
+}
+
+// ---------------------------------------------------------------------------
+// OAuth resource metadata
+// ---------------------------------------------------------------------------
+
+/**
+ * The resource identifier for this MCP server.
+ * Falls back to the autogenerated resource_id from the Scalekit dashboard if
+ * MCP_SERVER_URL is not set.
+ */
+export function getResourceId(): string {
+  return process.env.MCP_SERVER_URL ?? process.env.SCALEKIT_RESOURCE_ID ?? "";
+}
+
+export function getMetadataEndpoint(): string {
+  const base = process.env.MCP_SERVER_URL ?? "";
+  return `${base}/.well-known/oauth-protected-resource`;
+}
+
+/** Scopes advertised by this MCP server (comma-separated env var). */
+export function getScopesSupported(): string[] {
+  return (process.env.MCP_SCOPES ?? "meta_ads:read").split(",").map((s) => s.trim());
+}
+
+/** Build the OAuth Protected Resource Metadata document (RFC 9728). */
+export function buildResourceMetadata() {
+  const envUrl = process.env.SCALEKIT_ENVIRONMENT_URL ?? "";
+  const resourceId = getResourceId();
+  const scaleKitResourceId = process.env.SCALEKIT_RESOURCE_ID ?? resourceId;
+
+  return {
+    resource: resourceId,
+    authorization_servers: [`${envUrl}/resources/${scaleKitResourceId}`],
+    bearer_methods_supported: ["header"],
+    resource_documentation: `${resourceId}/docs`,
+    scopes_supported: getScopesSupported(),
+  };
+}
+
+// ---------------------------------------------------------------------------
+// WWW-Authenticate header helpers
+// ---------------------------------------------------------------------------
+
+export const WWWHeader = {
+  key: "WWW-Authenticate",
+  value: () =>
+    `Bearer realm="OAuth", resource_metadata="${getMetadataEndpoint()}"`,
+};
+
+// ---------------------------------------------------------------------------
+// Express middleware
+// ---------------------------------------------------------------------------
+
+/**
+ * Auth middleware for the HTTP MCP server.
+ *
+ * - Bypasses `.well-known` paths (public discovery endpoints).
+ * - Extracts and validates the Bearer JWT issued by Scalekit.
+ * - Returns 401 with a proper WWW-Authenticate header on failure.
+ *
+ * Enabled only when OAUTH_ENABLED=true; otherwise passes through (useful for
+ * local development or stdio mode).
+ */
+export async function authMiddleware(
+  req: Request,
+  res: Response,
+  next: NextFunction
+): Promise<void> {
+  // Allow public discovery + health check without auth
+  if (req.path.includes(".well-known") || req.path === "/health") {
+    return next();
+  }
+
+  try {
+    const authHeader = req.headers["authorization"];
+    const token =
+      authHeader?.startsWith("Bearer ") ? authHeader.slice(7).trim() : null;
+
+    if (!token) {
+      res.status(401).set(WWWHeader.key, WWWHeader.value()).end();
+      return;
+    }
+
+    const resourceId = getResourceId();
+    const scalekit = getScalekitClient();
+
+    await scalekit.validateToken(token, {
+      audience: resourceId ? [resourceId] : undefined,
+    });
+
+    next();
+  } catch {
+    res.status(401).set(WWWHeader.key, WWWHeader.value()).end();
+  }
+}
+
+/**
+ * Scope-checking helper for individual tools that need finer-grained control.
+ *
+ * Usage:
+ *   await requireScope(req, res, "meta_ads:write");
+ *   // returns false and sends 403 if scope is missing
+ */
+export async function requireScope(
+  req: Request,
+  res: Response,
+  scope: string
+): Promise<boolean> {
+  const authHeader = req.headers["authorization"];
+  const token =
+    authHeader?.startsWith("Bearer ") ? authHeader.slice(7).trim() : null;
+
+  if (!token) {
+    res.status(401).set(WWWHeader.key, WWWHeader.value()).end();
+    return false;
+  }
+
+  try {
+    const resourceId = getResourceId();
+    const scalekit = getScalekitClient();
+    await scalekit.validateToken(token, {
+      audience: resourceId ? [resourceId] : undefined,
+      requiredScopes: [scope],
+    });
+    return true;
+  } catch {
+    res.status(403).json({
+      error: "insufficient_scope",
+      error_description: `Required scope: ${scope}`,
+      scope,
+    });
+    return false;
+  }
+}