Call a Tool on an MCP Server

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Demonstrates Mcp.CallTool, which calls the MCP tools/call method for a named tool, passing a JSON arguments object and receiving the tool's result. The example calls the Microsoft Learn microsoft_docs_search tool.

Tip: Code to parse the returned JSON can be generated with Chilkat's online tool at https://tools.chilkat.io/jsonParse.

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.JsonObject,
  Chilkat.Mcp;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  mcp: TMcp;
  args: TJsonObject;
  result: TJsonObject;

begin
  success := False;

  mcp := TMcp.Create;

  //  Connect to a public MCP (Model Context Protocol) server over its Streamable HTTP endpoint.  The
  //  Microsoft Learn MCP server is public and requires no authentication.
  success := mcp.Connect('https://learn.microsoft.com/api/mcp');
  if (success = False) then
    begin
      WriteLn(mcp.LastErrorText);
      Exit;
    end;

  //  Build the tool's input arguments.  The members required depend on the tool's input schema (see
  //  ListTools).  Here the Microsoft Learn "microsoft_docs_search" tool takes a search query.
  args := TJsonObject.Create;
  args.UpdateString('query','How do I create an Azure storage account?');

  //  Call the MCP tools/call method for the named tool.  The tool's result is placed in the result
  //  JsonObject.
  result := TJsonObject.Create;
  success := mcp.CallTool('microsoft_docs_search',args,result);
  if (success = False) then
    begin
      WriteLn(mcp.LastErrorText);
      Exit;
    end;

  result.EmitCompact := False;
  WriteLn(result.Emit());
  //  JSON parsing code for this result can be generated at Chilkat's online tool:
  //  https://tools.chilkat.io/jsonParse


  mcp.Free;
  args.Free;
  result.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.