svrnty-mcp-server/samples/CodexMcpServer/Tools/SearchCodexTool.cs

using System;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;
using Svrnty.MCP.Core;

namespace CodexMcpServer.Tools;

/// <summary>
/// MCP tool for searching CODEX documents.
/// Calls CODEX API /api/documents/search endpoint.
/// </summary>
public class SearchCodexTool : IMcpTool
{
    private readonly HttpClient _httpClient;
    private static readonly JsonDocument _schema = JsonDocument.Parse("""
    {
        "type": "object",
        "properties": {
            "query": {
                "type": "string",
                "description": "Search query to find relevant documents in CODEX"
            }
        },
        "required": ["query"]
    }
    """);

    public SearchCodexTool(HttpClient httpClient)
    {
        _httpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient));

        // Set base address if not already set
        if (_httpClient.BaseAddress == null)
        {
            _httpClient.BaseAddress = new Uri("http://localhost:5050");
        }
    }

    /// <inheritdoc/>
    public string Name => "search_codex";

    /// <inheritdoc/>
    public string Description => "Search CODEX documents by query text. Returns matching documents with relevance scores.";

    /// <inheritdoc/>
    public JsonDocument Schema => _schema;

    /// <inheritdoc/>
    public async Task<JsonDocument> ExecuteAsync(JsonDocument? arguments)
    {
        try
        {
            // Validate arguments
            if (arguments == null)
            {
                return CreateErrorResponse("Arguments cannot be null. Expected {\"query\": \"search text\"}");
            }

            var root = arguments.RootElement;
            if (!root.TryGetProperty("query", out var queryElement))
            {
                return CreateErrorResponse("Missing required parameter 'query'");
            }

            var query = queryElement.GetString();
            if (string.IsNullOrWhiteSpace(query))
            {
                return CreateErrorResponse("Query cannot be empty");
            }

            // Prepare request to CODEX API
            var requestBody = new
            {
                query = query
            };

            var content = new StringContent(
                JsonSerializer.Serialize(requestBody),
                Encoding.UTF8,
                "application/json"
            );

            // Call CODEX API
            var response = await _httpClient.PostAsync("/api/documents/search", content);

            if (!response.IsSuccessStatusCode)
            {
                var errorContent = await response.Content.ReadAsStringAsync();
                return CreateErrorResponse(
                    $"CODEX API returned error: {response.StatusCode}. {errorContent}"
                );
            }

            // Parse and return response
            var responseContent = await response.Content.ReadAsStringAsync();
            try
            {
                return JsonDocument.Parse(responseContent);
            }
            catch (JsonException ex)
            {
                return CreateErrorResponse($"Failed to parse CODEX API response: {ex.Message}");
            }
        }
        catch (HttpRequestException ex)
        {
            return CreateErrorResponse($"HTTP request failed: {ex.Message}");
        }
        catch (Exception ex)
        {
            return CreateErrorResponse($"Unexpected error: {ex.Message}");
        }
    }

    private static JsonDocument CreateErrorResponse(string message)
    {
        var error = new
        {
            error = message
        };
        return JsonDocument.Parse(JsonSerializer.Serialize(error));
    }
}