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<?php |
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/** |
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* Initialize method handler for MCP requests. |
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* |
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* @package McpAdapter |
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*/ |
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|
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declare( strict_types=1 ); |
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|
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namespace WP\MCP\Handlers\Initialize; |
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|
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use WP\MCP\Core\McpServer; |
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use WP\MCP\Core\McpVersionNegotiator; |
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use WP\McpSchema\Common\Lifecycle\DTO\Implementation; |
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use WP\McpSchema\Common\Protocol\DTO\InitializeResult; |
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use WP\McpSchema\Server\Lifecycle\DTO\ServerCapabilities; |
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|
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/** |
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* Handles the initialize MCP method. |
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*/ |
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class InitializeHandler { |
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/** |
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* The WordPress MCP instance. |
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* |
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* @var \WP\MCP\Core\McpServer |
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*/ |
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private McpServer $mcp; |
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|
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/** |
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* Constructor. |
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* |
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* @param \WP\MCP\Core\McpServer $mcp The WordPress MCP instance. |
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*/ |
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public function __construct( McpServer $mcp ) { |
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$this->mcp = $mcp; |
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} |
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|
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/** |
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* Handles the initialize request. |
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* |
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* Negotiates the protocol version with the client using McpVersionNegotiator. |
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* If the client requests a supported version, that version is used. Otherwise |
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* the server falls back to the latest supported version. |
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* |
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* @since 0.5.0 |
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* |
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* @param string $client_protocol_version The protocol version requested by the client. |
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* |
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* @return \WP\McpSchema\Common\Protocol\DTO\InitializeResult Response with server capabilities and information. |
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*/ |
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public function handle( string $client_protocol_version ): InitializeResult { |
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$negotiated_version = McpVersionNegotiator::negotiate( $client_protocol_version ); |
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|
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$server_info = Implementation::fromArray( |
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array( |
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'name' => $this->mcp->get_server_name(), |
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'version' => $this->mcp->get_server_version(), |
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) |
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); |
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|
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// Capabilities should only be advertised if they are implemented end-to-end. |
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// IMPORTANT: We set explicit boolean values (not empty arrays) to ensure proper JSON serialization. |
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// Empty arrays `[]` serialize as JSON arrays `[]`, but MCP spec requires JSON objects `{}`. |
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// Setting explicit values like `listChanged: false` produces associative arrays that serialize correctly. |
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$capabilities = ServerCapabilities::fromArray( |
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array( |
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'prompts' => array( 'listChanged' => false ), |
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'resources' => array( |
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'subscribe' => false, |
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'listChanged' => false, |
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), |
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'tools' => array( 'listChanged' => false ), |
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) |
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); |
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|
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$result = InitializeResult::fromArray( |
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array( |
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'protocolVersion' => $negotiated_version, |
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'capabilities' => $capabilities, |
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'serverInfo' => $server_info, |
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'instructions' => $this->mcp->get_server_description(), |
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) |
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); |
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|
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/** |
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* Filters the initialize response before returning to the client. |
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* |
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* Use this filter to modify server capabilities, instructions, or |
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* other initialization data dynamically. To modify the result, call |
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* `$result->toArray()`, change the data, and return |
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* `InitializeResult::fromArray( $modified_data )`. |
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* |
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* @since 0.5.0 |
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* |
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* @param \WP\McpSchema\Common\Protocol\DTO\InitializeResult $result The initialize result DTO. |
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* @param \WP\MCP\Core\McpServer $server The MCP server instance. |
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*/ |
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return apply_filters( 'mcp_adapter_initialize_response', $result, $this->mcp ); |
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} |
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} |
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|
