Add reference for Client class.

Author: zzap

docs/reference.md

@@ -21,11 +21,37 @@ This class follows an MCP client-server architecture, where:
 
 | Name | Description |
 | ---  | --- |
-| `AiCommand:__invoke( $args, $assoc_args )`  | <ul><li>Creates an AI server and client instance.</li><li>Registers tools & resources for AI processing.</li><li>Sends user input ($args[0]) to AI.</li><li>Outputs AI-generated results.</li></ul> |
-| `AiCommand:register_tools( $server, $client )`  | Registers functionality AI can invoke. See [available tools](tools.md). |
-| `AiCommand:register_resources( $server )`  | Registers structured datasets AI can access. See [available resources](). |
+| `AiCommand:__invoke( array $args, array $assoc_args )`  | <ul><li>Creates an AI server and client instance.</li><li>Registers tools & resources for AI processing.</li><li>Sends user input ($args[0]) to AI.</li><li>Outputs AI-generated results.</li></ul> |
+| `AiCommand:register_tools( Server $server, $client )`  | Registers functionality AI can invoke. See [available tools](tools.md). |
+| `AiCommand:register_resources( Server $server )`  | Registers structured datasets AI can access. See [available resources](). |
 
 
 ## `Client` class
 
+`Client` class is part of the `WP_CLI\AiCommand\MCP` namespace and serves as an intermediary between the WP-CLI and an AI-based service. It interacts with an MCP (Multi-Client Processor) AI service using JSON-RPC over a local server instance.
+
+The service supports:
+
+- Sending and receiving requests from the AI service.
+- Retrieving resources from the AI service.
+- Generating images via AI.
+- Processing AI-generated text responses.
+- Managing function calls and executing AI-invoked functions dynamically.
+
+### Properties
+
+| Name | Visibility modifier | Description |
+| ---  | --- | --- |
+| `$server`  | private | An instance of MCPServer. |
+
+### Methods
+
+| Name | Description |
+| ---  | --- |
+| `Client:__construct( Server $server )`  | Constructor |
+| `Client:send_request( string $method, array $params = [] )`  | Constructs a JSON-RPC request, sends it to the AI service, and decodes the response. |
+| `Client:__call( string $name, array $arguments )`  | A magic method to call any AI service method dynamically. |
+| `Client:list_resources()`  | Retrieves available AI-generated content. |
+| `Client:read_resource( string $uri )`  | Reads a specific AI-generated resource. |
+
 ## `Server` class