| 1 | using System.Collections.Frozen; |
| 2 | using System.Text.Json; |
| 3 | using ModelContextProtocol.Protocol; |
| 4 | using ModelContextProtocol.Server; |
| 5 | using OpenAgentRegistry.Mcp; |
| 6 | |
| 7 | const string DefaultBaseUrl = "http://127.0.0.1:8765"; |
| 8 | |
| 9 | var baseUrl = Environment.GetEnvironmentVariable("OAR_BASE_URL")?.Trim(); |
| 10 | if (string.IsNullOrWhiteSpace(baseUrl)) |
| 11 | baseUrl = DefaultBaseUrl; |
| 12 | |
| 13 | if (!Uri.TryCreate(baseUrl, UriKind.Absolute, out var baseUri)) |
| 14 | { |
| 15 | Console.Error.WriteLine("OAR_BASE_URL must be an absolute URL."); |
| 16 | return 1; |
| 17 | } |
| 18 | |
| 19 | using var http = new HttpClient { BaseAddress = baseUri }; |
| 20 | http.DefaultRequestHeaders.Accept.ParseAdd("application/json"); |
| 21 | |
| 22 | var client = new RegistryApiClient(http); |
| 23 | var toolsList = ToolCatalog.Build(); |
| 24 | |
| 25 | var options = new McpServerOptions |
| 26 | { |
| 27 | ServerInfo = new Implementation { Name = "OpenAgentRegistryMcp", Version = "0.1.0" }, |
| 28 | ServerInstructions = ServerInstructions.Text, |
| 29 | ProtocolVersion = "2024-11-05", |
| 30 | Capabilities = new ServerCapabilities { Tools = new ToolsCapability { ListChanged = false } }, |
| 31 | Handlers = new McpServerHandlers |
| 32 | { |
| 33 | ListToolsHandler = (_, _) => ValueTask.FromResult(new ListToolsResult { Tools = toolsList }), |
| 34 | CallToolHandler = async (request, cancellationToken) => |
| 35 | { |
| 36 | var name = request.Params?.Name ?? ""; |
| 37 | var args = request.Params?.Arguments is IReadOnlyDictionary<string, JsonElement> dictionary |
| 38 | ? dictionary |
| 39 | : FrozenDictionary<string, JsonElement>.Empty; |
| 40 | |
| 41 | try |
| 42 | { |
| 43 | var result = await ToolHandlers.HandleAsync(name, client, args, cancellationToken).ConfigureAwait(false); |
| 44 | return new CallToolResult |
| 45 | { |
| 46 | Content = [new TextContentBlock { Text = result.Body }], |
| 47 | IsError = !result.IsSuccess, |
| 48 | }; |
| 49 | } |
| 50 | catch (ArgumentException ex) |
| 51 | { |
| 52 | return Error(ex.Message); |
| 53 | } |
| 54 | catch (HttpRequestException ex) |
| 55 | { |
| 56 | return Error($"Registry unreachable at {baseUri}: {ex.Message}"); |
| 57 | } |
| 58 | catch (Exception ex) |
| 59 | { |
| 60 | return Error(ex.Message); |
| 61 | } |
| 62 | }, |
| 63 | }, |
| 64 | }; |
| 65 | |
| 66 | static CallToolResult Error(string message) => |
| 67 | new() |
| 68 | { |
| 69 | Content = [new TextContentBlock { Text = $"Error: {message}" }], |
| 70 | IsError = true, |
| 71 | }; |
| 72 | |
| 73 | var transport = new StdioServerTransport("OpenAgentRegistryMcp"); |
| 74 | await using var server = McpServer.Create(transport, options); |
| 75 | await server.RunAsync(); |
| 76 | return 0; |
| 77 | |