Looking for hints on how to redefine/reload available tools at runtime

[eng-marani]

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Question Category

• Protocol Specification
• SDK Usage
• Server Implementation
• General Implementation
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Your Question

Suppose tools are defined as plugins, and while the MCP server is running someone is adding a new tool pugin.
What method should i call to inform clients that a new tool has been added/modified ?
Also, how to modify at runtime existing tools. Any example available ?

Paolo Marani

[eng-marani]

I have found this:

_mcpserver.SendNotificationAsync(NotificationMethods.ToolListChangedNotification);

But, how can i get McpServer in a controller with DI ?
It seems that IMcpServer interface do not exist, or i have found no example on how to add this as DI

Please help!

[eng-marani]

I've discovered that you can use DI by accessing ServiceProvider directly from your controller:

IServiceProvider _services;
public MyController(IServiceProvider services, ...) {  _services = services}

Then you can retrieve where needed MCP server options:

McpServerOptions mcpOptions = _services.GetService<IOptions<McpServerOptions>>()!.Value;

Using mcpOptions you have access to the ToolCollection, and removing/adding items there the toollistchange event is supposedly automatically raised.

mcpOptions.ToolCollection.Add(tool);

Unfortunately, despite McpInspector receive the notification, clients like Claude Desktop seem not to receive this event, and continue to see previous tools. SO i assume this behaviour is not pretty standardizen or well accepted by mainstream clients that are MCP aware..

Is my approach the right one to dynamically change tool definitions at runtime after the server has being built ?