Delphi MCP Server Prompts (3/4)

What Are MCP Prompt Requests?

In MCP, Prompts are structured templates that clients can discover and use to generate model inputs consistently.
Each MCP server exposes:

1. prompts/list — to enumerate available prompts.
2. prompts/get — to render a specific prompt with given arguments.
3. notifications/prompts/list_changed — to notify clients when the prompt catalog changes.

This allows large language models or agents to retrieve available templates and render them dynamically with context.

Listing Prompts

When a client calls prompts/list, your server should return an array of prompt definitions, including each prompt's name, description, and argument schema.

Example code that publishes a code review prompt: 

procedure TMainForm.FormCreate(Sender: TObject);
var
  oPrompt: TsgcAI_MCP_Prompt;
begin
  MCPServer.Prompts.Clear;
  oPrompt := MCPServer.Prompts.AddPrompt('CodeReview',
    'Asks the LLM to analyze code quality and suggest improvements');
  oPrompt.Arguments.AddArgument('code', 'The code to review', True);
end; 

Prompt Request

When a client issues a prompts.call JSON-RPC request, TsgcWSAPIServer_MCP hydrates the strongly-typed request object (including tool name and the provided arguments) before raising the OnMCPRequestPrompt event. Your handler populates the response payload which is then serialized back to the client, alongside a success HTTP status code.

A typical handler looks like this: 

procedure TFRMMCPServer.MCPServerMCPRequestPrompt(Sender: TObject;
  const aSession: TsgcAI_MCP_Session; const aRequest: TsgcAI_MCP_Request_PromptsGet;
  const aResponse: TsgcAI_MCP_Response_PromptsGet);
begin
  if aRequest.Params.Name = 'CodeReview' then
  begin
    aResponse.Result.Description := 'Code review prompt';
    aResponse.Result.Messages.AddText('user',
      'Please review this Delphi code: ShowMessage(''Hello World'' ');
  end;
end; 

With MCP Prompts now integrated into sgcWebSockets 2025.9.0, developers can create AI-aware WebSocket servers that expose structured, discoverable, and dynamic prompts — bridging the gap between LLMs and real-time application data. 

Learn More

For in-depth documentation and component reference, visit:

sgcWebSockets MCP Prompts Server Guide 

Find below a Delphi MCP Server Demo for Windows