5. Plugin Architecture

The plugin architecture enables third-party developers to extend agent capabilities with standardized interfaces.

5.1 Agent Plugin Base Class

abstract class WP_Agent_Plugin {
    
    /**
     * Register tools this plugin provides to agents
     */
    abstract public function register_tools(): array;
    
    /**
     * Get the system prompt for this plugin's domain
     */
    abstract public function get_system_prompt(): string;
    
    /**
     * Define guardrails for this plugin's actions
     */
    public function get_guardrails(): array {
        return [
            'requires_approval' => [],
            'rate_limits' => [],
            'scope' => 'current_user'
        ];
    }
    
    /**
     * Handle agent decisions in this plugin's domain
     */
    public function handle_decision( WP_Agent_Decision $decision ): WP_Agent_Result;
}

5.2 Example: WooCommerce Agent Extension

/**
 * Plugin Name: WooCommerce Agent Extension
 * Agent Capabilities: order_management, inventory_prediction, customer_service
 */

class WC_Agent_Extension extends WP_Agent_Plugin {
    
    public function register_tools(): array {
        return [
            'check_inventory' => [
                'callback'    => [$this, 'tool_check_inventory'],
                'description' => 'Check current inventory levels for a product',
                'parameters'  => [
                    'product_id' => ['type' => 'integer', 'required' => true]
                ]
            ],
            'process_refund' => [
                'callback'    => [$this, 'tool_process_refund'],
                'description' => 'Process a refund for an order',
                'parameters'  => [
                    'order_id' => ['type' => 'integer', 'required' => true],
                    'amount'   => ['type' => 'number', 'required' => false],
                    'reason'   => ['type' => 'string', 'required' => true]
                ],
                'requires_approval' => true
            ],
            'recommend_products' => [
                'callback'    => [$this, 'tool_recommend_products'],
                'description' => 'Get product recommendations based on criteria'
            ],
            'track_order' => [
                'callback'    => [$this, 'tool_track_order'],
                'description' => 'Get tracking information for an order'
            ]
        ];
    }
    
    public function get_system_prompt(): string {
        return "You are a WooCommerce store assistant. Help customers track orders, process returns, find products, and answer questions.";
    }
    
    public function get_guardrails(): array {
        return [
            'requires_approval' => ['process_refund', 'cancel_order'],
            'rate_limits' => [
                'recommend_products' => '100/hour',
                'process_refund' => '10/hour'
            ],
            'scope' => 'current_user_orders'
        ];
    }
}

5.3 Agent Capability Manifest (plugin.json)

{
    "name": "WooCommerce Agent Extension",
    "version": "1.0.0",
    "agent": {
        "version": "1.0",
        "capabilities": [
            "order_management",
            "product_recommendation", 
            "customer_service"
        ],
        "tools": [
            {
                "name": "check_inventory",
                "description": "Check current inventory levels",
                "parameters": {
                    "type": "object",
                    "properties": {
                        "product_id": {
                            "type": "integer",
                            "description": "The WooCommerce product ID"
                        }
                    },
                    "required": ["product_id"]
                }
            }
        ],
        "guardrails": {
            "requires_approval": ["process_refund", "cancel_order"],
            "rate_limit": "100/hour",
            "scope": "current_user_orders"
        }
    }
}

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