fastmcp/docs/integrations/descope.mdx
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Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
2025-09-25 10:38:06 -04:00

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---
title: Descope 🤝 FastMCP
sidebarTitle: Descope
description: Secure your FastMCP server with Descope
icon: shield-check
tag: NEW
---
import { VersionBadge } from "/snippets/version-badge.mdx"
<VersionBadge version="2.12.4" />
This guide shows you how to secure your FastMCP server using [**Descope**](https://www.descope.com), a complete authentication and user management solution. This integration uses the [**Remote OAuth**](/servers/auth/remote-oauth) pattern, where Descope handles user login and your FastMCP server validates the tokens.
## Configuration
### Prerequisites
Before you begin, you will need:
1. To [sign up](https://www.descope.com/sign-up) for a Free Forever Descope account
2. Your **Project ID** from the [Descope Console](https://app.descope.com/settings/project)
3. Your FastMCP server's URL (can be localhost for development, e.g., `http://localhost:3000`)
### Step 1: Configure Descope
<Steps>
<Step title="Enable Dynamic Client Registration">
1. Go to the [Inbound Apps page](https://app.descope.com/apps/inbound) of the Descope Console
2. Click **DCR Settings**
3. Enable **Dynamic Client Registration (DCR)**
4. Define allowed scopes
<Warning>
DCR is required for FastMCP clients to automatically register with your authentication server.
</Warning>
</Step>
<Step title="Note Your Project ID">
Save your Project ID from [Project Settings](https://app.descope.com/settings/project):
```
Project ID: P2abc...123
```
</Step>
</Steps>
### Step 2: Environment Setup
Create a `.env` file with your Descope configuration:
```bash
DESCOPE_PROJECT_ID=P2abc...123 # Your Descope Project ID
DESCOPE_BASE_URL=https://api.descope.com # Descope API URL
SERVER_URL=http://localhost:3000 # Your server's base URL
```
<Note>
You can find your project's Descope Base URL in the [Multi-Region Support Guide](https://docs.descope.com/management/project-settings/multi-regional).
</Note>
### Step 3: FastMCP Configuration
Create your FastMCP server file and use the DescopeProvider to handle all the OAuth integration automatically:
```python server.py
from fastmcp import FastMCP
from fastmcp.server.auth.providers.descope import DescopeProvider
# The DescopeProvider automatically discovers Descope endpoints
# and configures JWT token validation
auth_provider = DescopeProvider(
project_id=DESCOPE_PROJECT_ID, # Your Descope Project ID
base_url=SERVER_URL, # Your server's public URL
descope_base_url=DESCOPE_BASE_URL, # Descope API base URL
)
# Create FastMCP server with auth
mcp = FastMCP(name="My Descope Protected Server", auth=auth_provider)
```
## Testing
To test your server, you can use the `fastmcp` CLI to run it locally. Assuming you've saved the above code to `server.py` (after replacing the `project_id`, `base_url`, and `descope_base_url` with your actual values!), you can run the following command:
```bash
fastmcp run server.py --transport http --port 8000
```
Now, you can use a FastMCP client to test that you can reach your server after authenticating:
```python
from fastmcp import Client
import asyncio
async def main():
async with Client("http://localhost:8000/mcp/", auth="oauth") as client:
assert await client.ping()
if __name__ == "__main__":
asyncio.run(main())
```
## Environment Variables
For production deployments, use environment variables instead of hardcoding credentials.
### Provider Selection
Setting this environment variable allows the Descope provider to be used automatically without explicitly instantiating it in code.
<Card>
<ParamField path="FASTMCP_SERVER_AUTH" default="Not set">
Set to `fastmcp.server.auth.providers.descope.DescopeProvider` to use Descope authentication.
</ParamField>
</Card>
### Descope-Specific Configuration
These environment variables provide default values for the Descope provider, whether it's instantiated manually or configured via `FASTMCP_SERVER_AUTH`.
<Card>
<ParamField path="FASTMCP_SERVER_AUTH_DESCOPEPROVIDER_PROJECT_ID" required>
Your Descope Project ID from the [Descope Console](https://app.descope.com/settings/project)
</ParamField>
<ParamField path="FASTMCP_SERVER_AUTH_DESCOPEPROVIDER_BASE_URL" required>
Public URL of your FastMCP server (e.g., `https://your-server.com` or `http://localhost:8000` for development)
</ParamField>
<ParamField path="FASTMCP_SERVER_AUTH_DESCOPEPROVIDER_DESCOPE_BASE_URL" default="https://api.descope.com">
Descope API base URL for your [region/environment](https://docs.descope.com/management/project-settings/multi-regional)
</ParamField>
</Card>
Example `.env` file:
```bash
# Use the Descope provider
FASTMCP_SERVER_AUTH=fastmcp.server.auth.providers.descope.DescopeProvider
# Descope configuration
FASTMCP_SERVER_AUTH_DESCOPEPROVIDER_PROJECT_ID=P2abc...123
FASTMCP_SERVER_AUTH_DESCOPEPROVIDER_BASE_URL=https://your-server.com
FASTMCP_SERVER_AUTH_DESCOPEPROVIDER_DESCOPE_BASE_URL=https://api.descope.com
```
With environment variables set, your server code simplifies to:
```python server.py
from fastmcp import FastMCP
# Authentication is automatically configured from environment
mcp = FastMCP(name="My Descope Protected Server")
```