Discord OAuth 🤝 FastMCP

Secure your FastMCP server with Discord OAuth

New in version 2.13.2

This guide shows you how to secure your FastMCP server using Discord OAuth. Since Discord doesn’t support Dynamic Client Registration, this integration uses the OAuth Proxy pattern to bridge Discord’s traditional OAuth with MCP’s authentication requirements.

Configuration

Prerequisites

Before you begin, you will need:

1. A Discord Account with access to create applications
2. Your FastMCP server’s URL (can be localhost for development, e.g., http://localhost:8000)

Step 1: Create a Discord Application

Create an application in the Discord Developer Portal to get the credentials needed for authentication:

1. Navigate to Discord Developer Portal

   Go to the Discord Developer Portal.

   Click “New Application” and give it a name users will recognize (e.g., “My FastMCP Server”).

2. Configure OAuth2 Settings

   In the left sidebar, click “OAuth2”.

   In the Redirects section, click “Add Redirect” and enter your callback URL:

   • For development: http://localhost:8000/auth/callback
   • For production: https://your-domain.com/auth/callback

   The redirect URL must match exactly. The default path is /auth/callback, but you can customize it using the redirect_path parameter. Discord allows http://localhost URLs for development. For production, use HTTPS.

3. Save Your Credentials

   On the same OAuth2 page, you’ll find:

   • Client ID: A numeric string like 12345
   • Client Secret: Click “Reset Secret” to generate one

   Store these credentials securely. Never commit them to version control. Use environment variables or a secrets manager in production.

Step 2: FastMCP Configuration

Create your FastMCP server using the DiscordProvider, which handles Discord’s OAuth flow automatically:

server.py

from fastmcp import FastMCP
from fastmcp.server.auth.providers.discord import DiscordProvider

auth_provider = DiscordProvider(
    client_id="12345",      # Your Discord Application Client ID
    client_secret="your-client-secret",    # Your Discord OAuth Client Secret
    base_url="http://localhost:8000",      # Must match your OAuth configuration
)

mcp = FastMCP(name="Discord Secured App", auth=auth_provider)

@mcp.tool
async def get_user_info() -> dict:
    """Returns information about the authenticated Discord user."""
    from fastmcp.server.dependencies import get_access_token

    token = get_access_token()
    return {
        "discord_id": token.claims.get("sub"),
        "username": token.claims.get("username"),
        "avatar": token.claims.get("avatar"),
    }

Testing

Running the Server

Start your FastMCP server with HTTP transport to enable OAuth flows:

fastmcp run server.py --transport http --port 8000

Your server is now running and protected by Discord OAuth authentication.

Testing with a Client

Create a test client that authenticates with your Discord-protected server:

test_client.py

from fastmcp import Client
import asyncio

async def main():
    async with Client("http://localhost:8000/mcp", auth="oauth") as client:
        print("✓ Authenticated with Discord!")

        result = await client.call_tool("get_user_info")
        print(f"Discord user: {result['username']}")

if __name__ == "__main__":
    asyncio.run(main())

When you run the client for the first time:

1. Your browser will open to Discord’s authorization page
2. Sign in with your Discord account and authorize the app
3. After authorization, you’ll be redirected back
4. The client receives the token and can make authenticated requests

The client caches tokens locally, so you won’t need to re-authenticate for subsequent runs unless the token expires or you explicitly clear the cache.

Discord Scopes

Discord OAuth supports several scopes for accessing different types of user data:

Scope	Description
identify	Access username, avatar, and discriminator (default)
email	Access the user’s email address
guilds	Access the user’s list of servers
guilds.join	Ability to add the user to a server

To request additional scopes:

auth_provider = DiscordProvider(
    client_id="...",
    client_secret="...",
    base_url="http://localhost:8000",
    required_scopes=["identify", "email"],
)

Production Configuration

For production deployments with persistent token management across server restarts, configure jwt_signing_key and client_storage:

server.py

import os
from fastmcp import FastMCP
from fastmcp.server.auth.providers.discord import DiscordProvider
from key_value.aio.stores.redis import RedisStore
from key_value.aio.wrappers.encryption import FernetEncryptionWrapper
from cryptography.fernet import Fernet

auth_provider = DiscordProvider(
    client_id="12345",
    client_secret=os.environ["DISCORD_CLIENT_SECRET"],
    base_url="https://your-production-domain.com",

    jwt_signing_key=os.environ["JWT_SIGNING_KEY"],
    client_storage=FernetEncryptionWrapper(
        key_value=RedisStore(
            host=os.environ["REDIS_HOST"],
            port=int(os.environ["REDIS_PORT"])
        ),
        fernet=Fernet(os.environ["STORAGE_ENCRYPTION_KEY"])
    )
)

mcp = FastMCP(name="Production Discord App", auth=auth_provider)

Parameters (jwt_signing_key and client_storage) work together to ensure tokens and client registrations survive server restarts. Wrap your storage in FernetEncryptionWrapper to encrypt sensitive OAuth tokens at rest - without it, tokens are stored in plaintext. Store secrets in environment variables and use a persistent storage backend like Redis for distributed deployments.

For complete details on these parameters, see the OAuth Proxy documentation.

Environment Variables

For production deployments, use environment variables instead of hardcoding credentials.

Provider Selection

Setting this environment variable allows the Discord provider to be used automatically without explicitly instantiating it in code.

FASTMCP_SERVER_AUTH · default: "Not set"

Set to fastmcp.server.auth.providers.discord.DiscordProvider to use Discord authentication.

Discord-Specific Configuration

These environment variables provide default values for the Discord provider, whether it’s instantiated manually or configured via FASTMCP_SERVER_AUTH.

FASTMCP_SERVER_AUTH_DISCORD_CLIENT_ID · required

Your Discord Application Client ID (e.g., 12345)

FASTMCP_SERVER_AUTH_DISCORD_CLIENT_SECRET · required

Your Discord OAuth Client Secret

FASTMCP_SERVER_AUTH_DISCORD_BASE_URL · default: "http://localhost:8000"

Public URL where OAuth endpoints will be accessible (includes any mount path)

FASTMCP_SERVER_AUTH_DISCORD_ISSUER_URL · default: "Uses BASE_URL"

Issuer URL for OAuth metadata (defaults to BASE_URL). Set to root-level URL when mounting under a path prefix to avoid 404 logs. See HTTP Deployment guide for details.

FASTMCP_SERVER_AUTH_DISCORD_REDIRECT_PATH · default: "/auth/callback"

Redirect path configured in your Discord OAuth settings

FASTMCP_SERVER_AUTH_DISCORD_REQUIRED_SCOPES · default: "[\"identify\"]"

Comma-, space-, or JSON-separated list of required Discord scopes (e.g., identify,email or ["identify","email"])

FASTMCP_SERVER_AUTH_DISCORD_TIMEOUT_SECONDS · default: "10"

HTTP request timeout for Discord API calls

Example .env file:

FASTMCP_SERVER_AUTH=fastmcp.server.auth.providers.discord.DiscordProvider

FASTMCP_SERVER_AUTH_DISCORD_CLIENT_ID=12345
FASTMCP_SERVER_AUTH_DISCORD_CLIENT_SECRET=your-client-secret
FASTMCP_SERVER_AUTH_DISCORD_BASE_URL=https://your-server.com
FASTMCP_SERVER_AUTH_DISCORD_REQUIRED_SCOPES=identify,email

With environment variables set, your server code simplifies to:

server.py

from fastmcp import FastMCP

mcp = FastMCP(name="Discord Secured App")

@mcp.tool
async def protected_tool(query: str) -> str:
    """A tool that requires Discord authentication to access."""
    return f"Processing authenticated request: {query}"