`json
{
"inputs": [
{
"type": "promptString",
"id": "functions-mcp-extension-system-key",
"description": "Azure Functions MCP Extension System Key",
"password": true
},
{
"type": "promptString",
"id": "functionapp-name",
"description": "Azure Functions App Name"
}
],
"servers": {
"remote-mcp-function": {
"type": "sse",
"url": "https://${input:functionapp-name}.azurewebsites.net/runtime/webhooks/mcp/sse",
"headers": {
"x-functions-key": "${input:functions-mcp-extension-system-key}"
}
},
"local-mcp-function": {
"type": "sse",
"url": "http://0.0.0.0:7071/runtime/webhooks/mcp/sse"
}
}
}
`

1. Click Start on the server remote-mcp-function, inside the mcp.json file:

1. Enter the name of the function app that you created in the Azure Portal, when prompted by VS Code.

1. Enter the Azure Functions MCP Extension System Key into the prompt. You can copy this from the Azure portal for your function app by going to the Functions menu item, then App Keys, and copying the mcp_extension key from the System Keys.

1. In Copilot chat agent mode enter a prompt to trigger the tool, e.g., select some code and enter this prompt

`plaintext
Say Hello
`

`plaintext
Save this snippet as snippet1
`

`plaintext
Retrieve snippet1 and apply to newFile.ts
`

Redeploy your code

You can run the azd up command as many times as you need to both provision your Azure resources and deploy code updates to your function app.

>[!NOTE]
>Deployed code files are always overwritten by the latest deployment package.

Clean up resources

When you're done working with your function app and related resources, you can use this command to delete the function app and its related resources from Azure and avoid incurring any further costs:

`shell
azd down
`

Source Code

The function code for the getSnippet and saveSnippet endpoints are defined in the TypeScript files in the src directory. The MCP function annotations expose these functions as MCP Server tools.

This shows the code for a few MCP server examples (get string, get object, save object):

`typescript
// Hello function - responds with hello message
export async function mcpToolHello(context: InvocationContext): Promise {
return "Hello I am MCP Tool!";
}

// Register the hello tool
app.mcpTool('hello', {
toolName: 'hello',
description: 'Simple hello world MCP Tool that responses with a hello message.',
handler: mcpToolHello
});

// GetSnippet function - retrieves a snippet by name
export async function getSnippet(_message: unknown, context: InvocationContext): Promise {
console.info('Getting snippet');

// Get snippet name from the tool arguments
const mcptoolargs = context.triggerMetadata.mcptoolargs as { snippetname?: string };
const snippetName = mcptoolargs?.snippetname;

console.info(Snippet name: ${snippetName});

if (!snippetName) {
return "No snippet name provided";
}

// Get the content from blob binding - properly retrieving from extraInputs
const snippetContent = context.extraInputs.get(blobInputBinding);

if (!snippetContent) {
return Snippet '${snippetName}' not found;
}

console.info(Retrieved snippet: ${snippetName});
return snippetContent as string;
}


// Register the GetSnippet tool
app.mcpTool('getsnippet', {
toolName: GET_SNIPPET_TOOL_NAME,
description: GET_SNIPPET_TOOL_DESCRIPTION,
toolProperties: [
{
propertyName: SNIPPET_NAME_PROPERTY_NAME,
propertyValue: PROPERTY_TYPE,
description: SNIPPET_NAME_PROPERTY_DESCRIPTION,
}
],
extraInputs: [blobInputBinding],
handler: getSnippet
});

// SaveSnippet function - saves a snippet with a name
export async function saveSnippet(_message: unknown, context: InvocationContext): Promise {
console.info('Saving snippet');

// Get snippet name and content from the tool arguments
const mcptoolargs = context.triggerMetadata.mcptoolargs as {
snippetname?: string;
snippet?: string;
};

const snippetName = mcptoolargs?.snippetname;
const snippet = mcptoolargs?.snippet;

if (!snippetName) {
return "No snippet name provided";
}

if (!snippet) {
return "No snippet content provided";
}

// Save the snippet to blob storage using the output binding
context.extraOutputs.set(blobOutputBinding, snippet);

console.info(Saved snippet: ${snippetName});
return snippet;
}

// Register the SaveSnippet tool
app.mcpTool('savesnippet', {
toolName: SAVE_SNIPPET_TOOL_NAME,
description: SAVE_SNIPPET_TOOL_DESCRIPTION,
toolProperties: [
{
propertyName: SNIPPET_NAME_PROPERTY_NAME,
propertyValue: PROPERTY_TYPE,
description: SNIPPET_NAME_PROPERTY_DESCRIPTION,
},
{
propertyName: SNIPPET_PROPERTY_NAME,
propertyValue: PROPERTY_TYPE,
description: SNIPPET_PROPERTY_DESCRIPTION,
}
],
extraOutputs: [blobOutputBinding],
handler: saveSnippet
});
`

Note that the host.json file also includes a reference to the experimental bundle, which is required for apps using this feature:

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

Next Steps

- Add [API Management]() to your MCP server
- Add [EasyAuth]() to your MCP server
- Enable VNET using VNET_ENABLED=true flag
- Learn more about [related MCP efforts from Microsoft]()