Implement io.modelcontextprotocol.server.Result class

[thekid]

This PR implements the functionality suggested in #13.

• Text
• Images
• Audio
• Resource links
• Embedded resources
• Structured content
• Errors

API

public class io.modelcontextprotocol.server.Result {
  public function __construct(array $struct)

  public static function cast(var $value): self
  public static function success(var $value): self
  public static function error(var $value): self
  public static function structured(var $object, ?string|iterable $text, ?bool $isError): self

  public function add(string $type, array $struct, array $annotations): self
  public function text(string $string, [:mixed] $annotations): self
  public function image(string|util.Bytes $data, string $mime, [:mixed] $annotations): self
  public function audio(string|util.Bytes $data, string $mime, [:mixed] $annotations): self
  public function link(string $uri, string $name, string $description, string $mime, [:mixed] $annotations): self
  public function resource(string $uri, string|util.Bytes $text, string $mime, [:mixed] $annotations): self
  public function struct(): array
}

Note: The constructor is left public intentionally should users wish full control over the generated resulting struct.

Example

use io\modelcontextprotocol\server\{Implementation, Tool, Param, Result};

#[Implementation]
class Weather {
  private $backing= [
    '8FXC2C43+QF' => [
      'temperature' => 22.5,
      'conditions'  => 'Partly cloudy',
      'humidity'    => 65,
    ],
  ];

  private function lookup(string $city): ?string {
    // TBI
  }

  #[Tool]
  public function for(#[Param] string $city): Result {
    if ($code= $this->lookup($city)) {
      return Result::success($this->backing[$code]);
    } else {
      return Result::error('Cannot find city '.$city);
    }
  }
}

See also

• https://modelcontextprotocol.io/specification/2025-11-25/server/tools#tool-result
• https://modelcontextprotocol.io/specification/2025-11-25/server/tools#structured-content
• https://modelcontextprotocol.io/specification/2025-11-25/server/tools#error-handling
• https://modelcontextprotocol.io/specification/2025-11-25/server/tools#annotations

[thekid]

Released in https://github.com/xp-forge/mcp/releases/tag/v0.11.0