A2AAgentHook.cs

using BotSharp.Abstraction.Agents;
using BotSharp.Abstraction.Agents.Enums;
using BotSharp.Abstraction.Agents.Models;
using BotSharp.Abstraction.Agents.Settings;
using BotSharp.Abstraction.Functions.Models;
using BotSharp.Core.A2A.Services;
using BotSharp.Core.A2A.Settings;
using System.Text.Json;

namespace BotSharp.Core.A2A.Hooks;

public class A2AAgentHook : AgentHookBase
{
    public override string SelfId => string.Empty;

    private readonly A2ASettings _a2aSettings;
    private readonly IA2AService _a2aService;

    public A2AAgentHook(IServiceProvider services, IA2AService a2aService, A2ASettings a2aSettings, AgentSettings agentSettings)
        : base(services, agentSettings)
    {
        _a2aService = a2aService;
        _a2aSettings = a2aSettings;
    }

    public override bool OnAgentLoading(ref string id)
    {
        var agentId = id;
        var remoteConfig = _a2aSettings.Agents?.FirstOrDefault(x => x.Id == agentId);
        if (remoteConfig != null)
        {
            return true;
        }
        return base.OnAgentLoading(ref id);
    }

    public override void OnAgentLoaded(Agent agent)
    {
        // Check if this is an A2A remote agent
        if (agent.Type != AgentType.A2ARemote)
        {
            return;
        }

        var remoteConfig = _a2aSettings.Agents?.FirstOrDefault(x => x.Id == agent.Id);
        if (remoteConfig != null)
        {
            var agentCard = _a2aService.GetCapabilitiesAsync(remoteConfig.Endpoint).GetAwaiter().GetResult();
            if (agentCard != null)
            {
                agent.Name = agentCard.Name;
                agent.Description = agentCard.Description;
                agent.Instruction = $"You are a proxy interface for an external intelligent service named '{agentCard.Name}'. " +
                                    $"Your ONLY goal is to forward the user's request verbatim to the external service. " +
                                    $"You must use the function 'delegate_to_a2a' to communicate with it. " +
                                    $"Do not attempt to answer the question yourself.";

                var properties = new Dictionary<string, object>
                {
                    {
                        "user_query",
                        new
                        {
                            type = "string",
                            description = "The exact user request or task description to be forwarded."
                        }
                    }
                };

                var propertiesJson = JsonSerializer.Serialize(properties);
                var propertiesDocument = JsonDocument.Parse(propertiesJson);

                agent.Functions.Add(new FunctionDef
                {
                    Name = "delegate_to_a2a",
                    Description = $"Delegates the task to the external {remoteConfig.Name} via A2A protocol.",
                    Parameters = new FunctionParametersDef()
                    {
                        Type = "object",
                        Properties = propertiesDocument,
                        Required = new List<string> { "user_query" }
                    }
                });
            }
        }
        base.OnAgentLoaded(agent);
    }
}