Decouple Handlers and Collections from protocol types

[jozkee]

Decouple Handlers and Collections (e.g. ToolsHandler and ToolsCollection) from Capabilities by promoting them to the options types.
Also, group all handlers in container classes, for server, I decided to move McpServerHandlers down to Mcp.Core and move the NotificationHandlers there too.

Breaking Changes (Migration Summary)

Handlers and collections in the Capabilities types are now obsolete; they've been moved to McpClientOptions and McpServerOptions.

1. Collections

Replace usages of the obsolete collections with the corresponding collections on the options types:

Old

new McpServerOptions() 
{
    Capabilities = new() 
    {
        Tools = new() 
        { 
            ToolCollection = [McpServerTool.Create(...)] 
        }
    }
};

New

new McpServerOptions()
{
    ToolCollection = [McpServerTool.Create(...)]
};

2. Handlers

Replace usages of the obsolete handlers with the corresponding handlers on the options types:

Old

new McpServerOptions()
{
    Capabilities = new()
    {
        Tools = new()
        {
            CallToolHandler = (request, ct) => { ... }
        }
    }
};

New

new McpServerOptions()
{
    Handlers = new()
    {
        CallToolHandler = (request, ct) => { ... }
    }
};

Mapping (Old → New)

Old	New
myClientOptions.Capabilities.NotificationHandlers	myClientOptions.Handlers.NotificationHandlers
myClientOptions.Capabilities.Elicitation.ElicitationHandler	myClientOptions.Handlers.ElicitationHandler
myClientOptions.Capabilities.Roots.RootsHandler	myClientOptions.Handlers.RootsHandler
myClientOptions.Capabilities.Sampling.SamplingHandler	myClientOptions.Handlers.SamplingHandler
myServerOptions.Capabilities.NotificationHandlers	myServerOptions.Handlers.NotificationHandlers
myServerOptions.Capabilities.Completions.CompleteHandler	myServerOptions.Handlers.CompleteHandler
myServerOptions.Capabilities.Logging.SetLoggingLevelHandler	myServerOptions.Handlers.SetLoggingLevelHandler
myServerOptions.Capabilities.Prompts.ListPromptsHandler	myServerOptions.Handlers.ListPromptsHandler
myServerOptions.Capabilities.Prompts.GetPromptHandler	myServerOptions.Handlers.GetPromptHandler
myServerOptions.Capabilities.Prompts.PromptCollection	myServerOptions.PromptCollection
myServerOptions.Capabilities.Resources.ListResourceTemplatesHandler	myServerOptions.Handlers.ListResourceTemplatesHandler
myServerOptions.Capabilities.Resources.ListResourcesHandler	myServerOptions.Handlers.ListResourcesHandler
myServerOptions.Capabilities.Resources.ReadResourceHandler	myServerOptions.Handlers.ReadResourceHandler
myServerOptions.Capabilities.Resources.SubscribeToResourcesHandler	myServerOptions.Handlers.SubscribeToResourcesHandler
myServerOptions.Capabilities.Resources.UnsubscribeFromResourcesHandler	myServerOptions.Handlers.UnsubscribeFromResourcesHandler
myServerOptions.Capabilities.Resources.ResourceCollection	myServerOptions.ResourceCollection
myServerOptions.Capabilities.Tools.ListToolsHandler	myServerOptions.Handlers.ListToolsHandler
myServerOptions.Capabilities.Tools.CallToolHandler	myServerOptions.Handlers.CallToolHandler
myServerOptions.Capabilities.Tools.ToolCollection	myServerOptions.ToolCollection

[eiriktsarpalis]

Related to this discussion, does removing the check on the capability make this diverge from the MCP spec?

[jozkee]

Sorry, how it would diverge? The logic below will initialize the capabilities if they are null, if a handler is provided.