Add mcp auth documentation

daprdocs/content/en/developing-applications/mcp/_index.md

@@ -0,0 +1,12 @@
+---
+type: docs
+title: "MCP"
+linkTitle: "MCP"
+weight: 25
+description: "Dapr helps developers run secure and reliable MCP servers"
+---
+
+###  What does Dapr do for MCP servers?
+
+Using Dapr, developers can interact securely with MCP servers and enable fine-grained ACLs with built-in tracing and metrics, as well as resiliency policies to handle situations where an MCP server might be down or unresponsive.
+

daprdocs/content/en/developing-applications/mcp/mcp-authentication.md

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+---
+type: docs
+title: "Authenticating an MCP server"
+linkTitle: "Getting Started"
+weight: 20
+description: "How to enable MCP client-side and server-side authentication"
+---
+
+## Overview
+
+The MCP specification does not mandate any form of authentication between an MCP client and server. The security model is left to the user to plan and implement, which creates a maintanance burden on developers and opens up MCP servers to various attack surfaces.
+
+While MCP servers lack identity, OAuth2 is a well established standard that can be used to properly authenticate MCP clients to MCP servers.
+
+OAuth2 becomes essential when MCP servers are:
+
+* Multi-tenant
+* Remote
+* Cloud-hosted
+* Connected to confidential systems
+* Performing privileged actions on behalf of a user
+* Exposing tools that must be permission-gated
+
+Dapr enables seamless OAuth2 authentication between MCP clients and servers using [middleware]({{% ref "middleware" %}}) components.
+
+## Types of authentication
+
+Dapr supports two critical authentication mechanisms for production grade deployments of MCP servers - Client-side and Server-side.
+
+### Client-side Authentication
+
+The client initiates OAuth2 to obtain an access token and includes it when connecting to the MCP server.
+This proves the user’s identity and permissions and is required for remote, sensitive, or multi-tenant MCP servers.
+It ensures the server can trust who is calling and what scopes the client is allowed to use.
+
+### Server-side Authentication
+
+The server validates the client’s token or, if missing or insufficient, triggers an OAuth2 login or scope upgrade.
+This is needed for cloud-hosted or shared MCP servers, tenant-aware systems, and integrations that require user-specific authorization.
+It enforces access control, isolates users, and protects privileged tools and data.
+
+## How to enable Client-side Authentication
+
+### Define the MCP Server as an HTTPEndpoint
+
+Dapr allows developers and operators to model remote HTTP services as resources that can be governed and invoked using the Dapr [Service Invocation API]({{% ref "service-invocation-overview" %}}).
+
+```yaml
+apiVersion: dapr.io/v1alpha1
+kind: HTTPEndpoint
+metadata:
+  name: "mcp-server"
+spec:
+  baseUrl: https://my-mcp-server:443
+  headers:
+  - name: "Accept"
+    value: "text/event-stream"
+```
+
+### Define the OAuth2 middleware and configuration components
+
+```yaml
+apiVersion: dapr.io/v1alpha1
+kind: Component
+metadata:
+  name: oauth2
+spec:
+  type: middleware.http.oauth2
+  version: v1
+  metadata:
+  - name: clientId
+    value: "<client-id>"
+  - name: clientSecret
+    value: "<client-secret>"
+  - name: authURL
+    value: "<authorization-url>"
+  - name: tokenURL
+    value: "<token-url>"
+  - name: scopes
+    value: "<comma-separated scopes>"
+```
+
+Next, create the configuration component.
+
+```yaml
+piVersion: dapr.io/v1alpha1
+kind: Configuration
+metadata:
+  name: auth
+spec:
+  tracing:
+    samplingRate: "1"
+  httpPipeline:
+    handlers:
+    - name: oauth2 # reference the oauth component here
+      type: middleware.http.oauth2    
+```
+
+*Note: visit [this link]({{% ref "component-secrets.md" %}}) to read on how to provide secrets to Dapr components*
+
+### Call the MCP server using an MCP client
+
+```python
+import asyncio
+from mcp import ClientSession
+from mcp.transport.http import HttpClientTransport
+
+async def main():
+    # Address of the Dapr process
+    server_url = "http://localhost:3500/"
+
+    # Create an HTTP/SSE transport with a header to target our HTTPEndpoint defined above
+    transport = HttpClientTransport(
+        url=server_url,
+        headers={
+          "dapr-app-id": "mcp-server",
+        }
+        event_headers={
+            "Accept": "text/event-stream",
+        },
+    )
+
+    # Create an MCP session bound to the transport
+    async with ClientSession(transport) as session:
+        await session.initialize()
+
+        tools = await session.call("tools/list")
+        print("Server Tools:", tools))
+
+        await session.shutdown()
+
+if __name__ == "__main__":
+    asyncio.run(main())
+```
+
+### Run the MCP client with Dapr
+
+Put the YAML files above in `components` directory and run Dapr:
+
+```bash
+dapr run --app-id mcpclient --resources-path ./components --dapr-http-port 3500 --config ./config.yaml -- python mcpclient.py
+```
+
+If properly configured, the MCP client will cause Dapr to kick off an OAuth2 pipeline before connecting to the MCP server.  
+
+## How to enable Server-side Authentication
+
+### Define the OAuth2 middleware and configuration components
+
+We define a middleware component the same as above.
+
+```yaml
+apiVersion: dapr.io/v1alpha1
+kind: Component
+metadata:
+  name: oauth2
+spec:
+  type: middleware.http.oauth2
+  version: v1
+  metadata:
+  - name: clientId
+    value: "<client-id>"
+  - name: clientSecret
+    value: "<client-secret>"
+  - name: authURL
+    value: "<authorization-url>"
+  - name: tokenURL
+    value: "<token-url>"
+  - name: scopes
+    value: "<comma-separated scopes>"
+```
+
+Next, create the configuration component, with the modification of an `appHttpPipeline` field. This tells Dapr to apply the middleware for incoming calls.
+
+```yaml
+piVersion: dapr.io/v1alpha1
+kind: Configuration
+metadata:
+  name: auth
+spec:
+  tracing:
+    samplingRate: "1"
+  appHttpPipeline:
+    handlers:
+    - name: oauth2 # reference the oauth component here
+      type: middleware.http.oauth2    
+```
+
+### Run the MCP server with Dapr
+
+Put the YAML files above in `components` directory and run Dapr:
+
+```bash
+dapr run --app-id mcpclient --resources-path ./components --dapr-http-port 3500 --config ./config.yaml -- python mcpserver.py
+```
+
+If properly configured, Dapr will kick off an OAuth2 pipeline when a request for the MCP server arrives.