Getting Started with Remote MCP Servers using Azure Functions (Java)

This quick-start shows how to build and deploy a remote MCP server with Azure Functions (Java).
You can run it locally for debugging, then ship it to the cloud with azd up in minutes.
The server is secured by design (system keys + HTTPS), supports OAuth via EasyAuth or API Management, and can be isolated inside a VNet.

Watch the overview video.

Prerequisites

Purpose	Tool	Notes
Java build + run	JDK 17 (or newer)	Java 8 runtime still works but JDK 17 is recommended.
Local Functions runtime	Azure Functions Core Tools v4 ≥ 4.0.7030	Used by func start / mvn azure-functions:run.
Provision & deploy	Azure Developer CLI (azd)	Simplifies end-to-end deployment.
IDE (optional)	Visual Studio Code + Azure Functions extension	One-click debug & log streaming.
Blob Storage emulator	Docker to run Azurite	Needed only when running locally with UseDevelopmentStorage=true.

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Prepare your local environment

Why Azurite?
The SaveSnippet / GetSnippet tools persist snippets in Azure Blob Storage.
Azurite emulates that storage account on your dev machine.

docker run -p 10000:10000 -p 10001:10001 -p 10002:10002 \
       mcr.microsoft.com/azure-storage/azurite

If you prefer the Azurite VS Code extension, run “Azurite: Start” from the command palette instead.

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Run the MCP server locally

# 1 – Build the project
mvn clean package

# 2 – Start the Functions host (via Maven wrapper)
mvn azure-functions:run
#    └─ or use `func start` if you prefer

The SSE endpoint will be available at:

http://127.0.0.1:7071/runtime/webhooks/mcp/sse

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Try the local MCP server

A. GitHub Copilot in VS Code

1. Add MCP Server → choose HTTP (Server-Sent Events).

2. URL:

   http://127.0.0.1:7071/runtime/webhooks/mcp/sse
   

3. Give it any server-ID you like and save to User or Workspace settings.

4. List MCP Servers → Start your new server.

5. In Copilot Chat (agent-mode) try prompts such as:

   Say Hello
   Save this snippet as snippet1
   Retrieve snippet1 and apply to MyFile.java
   

6. When finished, Stop the server (command palette) and Ctrl+C the terminal running the function host.

B. MCP Inspector

# In a second terminal
npx @modelcontextprotocol/inspector node build/index.js
# If the Functions host isn’t running, start it:
# func start

• Open the Inspector UI (URL printed in the terminal).
• Transport: SSE.
• URL: http://127.0.0.1:7071/runtime/webhooks/mcp/sse → Connect.
• List Tools → pick one → Run Tool.

Stop both terminals with Ctrl+C when done.

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Deploy to Azure (remote MCP)

Want the function app inside a VNet before provisioning? Just set:

azd env set VNET_ENABLED true

Then provision + deploy in one step:

azd up

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Connect clients to the remote MCP server

The hosted SSE endpoint will be:

https://<FUNC_APP_NAME>.azurewebsites.net/runtime/webhooks/mcp/sse

Key required Grab the system key named mcp_extension from the Azure Portal or via CLI: az functionapp keys list --resource-group <rg> --name <func-app>

MCP Inspector

https://<FUNC_APP_NAME>.azurewebsites.net/runtime/webhooks/mcp/sse?code=<mcp_extension_key>

VS Code – GitHub Copilot

Add a header in mcp.json:

{
  "servers": {
    "remote-mcp-function": {
      "type": "sse",
      "url": "https://<FUNC_APP_NAME>.azurewebsites.net/runtime/webhooks/mcp/sse",
      "headers": {
        "x-functions-key": "<mcp_extension_key>"
      }
    },
    "local-mcp-function": {
      "type": "sse",
      "url": "http://127.0.0.1:7071/runtime/webhooks/mcp/sse"
    }
  }
}

Start remote-mcp-function and chat as usual in Copilot.

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Redeploy code

azd up   # Safe to run repeatedly—always overwrites the app with the latest build

Clean up

azd down

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Source Code Layout

Tool	Path	Description
HelloWorld	src/main/java/com/function/HelloWorld.java	Logs an argument then prints “Hello World”.
SaveSnippets / GetSnippets	src/main/java/com/function/Snippets.java	Saves / retrieves snippets to Blob Storage.

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How It Works

Click to expand

MCP Tool Trigger

@McpToolTrigger(
    toolName    = "saveSnippets",
    description = "Saves a text snippet to your snippets collection.",
    toolProperties = SAVE_SNIPPET_ARGUMENTS   // JSON schema string
)

• toolProperties defines the JSON payload expected from the client.
• At runtime the JSON is passed to your function in toolArguments.

Storage Bindings

@BlobOutput(
    name = "snippetOut",
    path = "snippets/{mcptoolargs.snippetName}.json",
    dataType = "binary")

• SaveSnippets writes to a blob; GetSnippets reads the same path.
• The default storage account is referenced with @StorageAccount("AzureWebJobsStorage").

Required SDK + Extension Bundle

<azure.functions.java.library.version>3.1.1-alpha</azure.functions.java.library.version>

// host.json
{
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle.Experimental",
    "version": "[4.*, 5.0.0)"
  }
}

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Next Steps

• Front your MCP server with API Management for fine-grained policies.
• Add EasyAuth to use your favourite OAuth provider (including Entra ID).
• Toggle VNet integration via VNET_ENABLED=true for network isolation.
• Explore the Model Context Protocol ecosystem for more tools.