Add OAuth authorization to a Workers-hosted MCP server so tool handlers receive verified user identity

Documented steps

1. Read https://developers.cloudflare.com/agents/model-context-protocol/authorization/ and the hardening guide https://developers.cloudflare.com/agents/model-context-protocol/guides/securing-mcp-server/ .
2. Install the library: @cloudflare/workers-oauth-provider .
3. Choose one of the four documented patterns: Cloudflare Access OAuth Provider (SSO/PIN); third-party provider handoff such as GitHub (npm create cloudflare@latest -- my-mcp-server-github-auth --template=cloudflare/ai/demos/remote-mcp-github-oauth); bring-your-own IdP (Stytch, Auth0, WorkOS, Descope); or fully self-handled OAuth.
4. Wire the top-level export: export default new OAuthProvider({ apiRoute: '/mcp', apiHandler: <your MCP handler>, defaultHandler: <your auth handler>, authorizeEndpoint: '/authorize', tokenEndpoint: '/token', clientRegistrationEndpoint: '/register' });
5. Create the KV namespace the provider uses for token storage: npx wrangler kv namespace create 'OAUTH_KV' , then add its id to wrangler.jsonc.
6. Inside tools, read verified identity with getMcpAuthContext() from 'agents/mcp/server' plus the SDK-supplied context.http.authInfo: const auth = getMcpAuthContext(); const user = auth?.props.name; const clientId = context.http?.authInfo?.clientId;
7. Local GitHub OAuth dev: register an OAuth App with homepage http://localhost:8788 and callback http://localhost:8788/callback, put GITHUB_CLIENT_ID and GITHUB_CLIENT_SECRET in .env, then npm start.
8. Production: register a separate OAuth App with production URLs, then npx wrangler secret put GITHUB_CLIENT_ID / GITHUB_CLIENT_SECRET / COOKIE_ENCRYPTION_KEY .
9. Implement your own consent dialog in defaultHandler rather than trusting cached or upstream consent; this is what prevents confused-deputy attacks.
10. Use CSRF-safe state cookies: HttpOnly; Secure; Path=/; SameSite=Lax, one-time-use, __Host- prefix on *.workers.dev, and bind KV-stored OAuth state (10 minute expiry) to the session cookie.
11. Deploy with npx wrangler deploy .