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| 1 | +package mcp |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "context" |
| 6 | + "encoding/json" |
| 7 | + "fmt" |
| 8 | + "net/http" |
| 9 | + "time" |
| 10 | + |
| 11 | + "github.com/mark3labs/mcp-go/mcp" |
| 12 | + "github.com/mark3labs/mcp-go/server" |
| 13 | + "golang.org/x/xerrors" |
| 14 | + |
| 15 | + "cdr.dev/slog" |
| 16 | + |
| 17 | + "github.com/coder/coder/v2/buildinfo" |
| 18 | + "github.com/coder/coder/v2/codersdk" |
| 19 | + "github.com/coder/coder/v2/codersdk/toolsdk" |
| 20 | +) |
| 21 | + |
| 22 | +const ( |
| 23 | + // MCPServerName is the name used for the MCP server. |
| 24 | + MCPServerName = "Coder" |
| 25 | + // MCPServerInstructions is the instructions text for the MCP server. |
| 26 | + MCPServerInstructions = "Coder MCP Server providing workspace and template management tools" |
| 27 | +) |
| 28 | + |
| 29 | +// Server represents an MCP HTTP server instance |
| 30 | +type Server struct { |
| 31 | + Logger slog.Logger |
| 32 | + |
| 33 | + // mcpServer is the underlying MCP server |
| 34 | + mcpServer *server.MCPServer |
| 35 | + |
| 36 | + // streamableServer handles HTTP transport |
| 37 | + streamableServer *server.StreamableHTTPServer |
| 38 | +} |
| 39 | + |
| 40 | +// NewServer creates a new MCP HTTP server |
| 41 | +func NewServer(logger slog.Logger) (*Server, error) { |
| 42 | + // Create the core MCP server |
| 43 | + mcpSrv := server.NewMCPServer( |
| 44 | + MCPServerName, |
| 45 | + buildinfo.Version(), |
| 46 | + server.WithInstructions(MCPServerInstructions), |
| 47 | + ) |
| 48 | + |
| 49 | + // Create logger adapter for mcp-go |
| 50 | + mcpLogger := &mcpLoggerAdapter{logger: logger} |
| 51 | + |
| 52 | + // Create streamable HTTP server with configuration |
| 53 | + streamableServer := server.NewStreamableHTTPServer(mcpSrv, |
| 54 | + server.WithHeartbeatInterval(30*time.Second), |
| 55 | + server.WithLogger(mcpLogger), |
| 56 | + ) |
| 57 | + |
| 58 | + return &Server{ |
| 59 | + Logger: logger, |
| 60 | + mcpServer: mcpSrv, |
| 61 | + streamableServer: streamableServer, |
| 62 | + }, nil |
| 63 | +} |
| 64 | + |
| 65 | +// ServeHTTP implements http.Handler interface |
| 66 | +func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) { |
| 67 | + s.streamableServer.ServeHTTP(w, r) |
| 68 | +} |
| 69 | + |
| 70 | +// RegisterTools registers all available MCP tools with the server |
| 71 | +func (s *Server) RegisterTools(client *codersdk.Client) error { |
| 72 | + if client == nil { |
| 73 | + return xerrors.New("client cannot be nil: MCP HTTP server requires authenticated client") |
| 74 | + } |
| 75 | + |
| 76 | + // Create tool dependencies |
| 77 | + toolDeps, err := toolsdk.NewDeps(client) |
| 78 | + if err != nil { |
| 79 | + return xerrors.Errorf("failed to initialize tool dependencies: %w", err) |
| 80 | + } |
| 81 | + |
| 82 | + // Register all available tools |
| 83 | + for _, tool := range toolsdk.All { |
| 84 | + s.mcpServer.AddTools(mcpFromSDK(tool, toolDeps)) |
| 85 | + } |
| 86 | + |
| 87 | + return nil |
| 88 | +} |
| 89 | + |
| 90 | +// mcpFromSDK adapts a toolsdk.Tool to go-mcp's server.ServerTool |
| 91 | +func mcpFromSDK(sdkTool toolsdk.GenericTool, tb toolsdk.Deps) server.ServerTool { |
| 92 | + if sdkTool.Schema.Properties == nil { |
| 93 | + panic("developer error: schema properties cannot be nil") |
| 94 | + } |
| 95 | + |
| 96 | + return server.ServerTool{ |
| 97 | + Tool: mcp.Tool{ |
| 98 | + Name: sdkTool.Name, |
| 99 | + Description: sdkTool.Description, |
| 100 | + InputSchema: mcp.ToolInputSchema{ |
| 101 | + Type: "object", |
| 102 | + Properties: sdkTool.Schema.Properties, |
| 103 | + Required: sdkTool.Schema.Required, |
| 104 | + }, |
| 105 | + }, |
| 106 | + Handler: func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) { |
| 107 | + var buf bytes.Buffer |
| 108 | + if err := json.NewEncoder(&buf).Encode(request.Params.Arguments); err != nil { |
| 109 | + return nil, xerrors.Errorf("failed to encode request arguments: %w", err) |
| 110 | + } |
| 111 | + result, err := sdkTool.Handler(ctx, tb, buf.Bytes()) |
| 112 | + if err != nil { |
| 113 | + return nil, err |
| 114 | + } |
| 115 | + return &mcp.CallToolResult{ |
| 116 | + Content: []mcp.Content{ |
| 117 | + mcp.NewTextContent(string(result)), |
| 118 | + }, |
| 119 | + }, nil |
| 120 | + }, |
| 121 | + } |
| 122 | +} |
| 123 | + |
| 124 | +// mcpLoggerAdapter adapts slog.Logger to the mcp-go util.Logger interface |
| 125 | +type mcpLoggerAdapter struct { |
| 126 | + logger slog.Logger |
| 127 | +} |
| 128 | + |
| 129 | +func (l *mcpLoggerAdapter) Infof(format string, v ...any) { |
| 130 | + l.logger.Info(context.Background(), fmt.Sprintf(format, v...)) |
| 131 | +} |
| 132 | + |
| 133 | +func (l *mcpLoggerAdapter) Errorf(format string, v ...any) { |
| 134 | + l.logger.Error(context.Background(), fmt.Sprintf(format, v...)) |
| 135 | +} |
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