chore(deps): update mcp-go (#155)

* chore(deps): update mcp-go

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

* fix: vendoring

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

---------

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

go.mod

@@ -29,7 +29,7 @@ require (
 	github.com/fsnotify/fsnotify v1.8.0
 	github.com/google/uuid v1.6.0
 	github.com/joho/godotenv v1.5.1
-	github.com/mark3labs/mcp-go v0.32.0
+	github.com/mark3labs/mcp-go v0.33.0
 	github.com/muesli/termenv v0.16.0
 	github.com/ncruces/go-sqlite3 v0.25.0
 	github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646

go.sum

@@ -165,8 +165,8 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
-github.com/mark3labs/mcp-go v0.32.0 h1:fgwmbfL2gbd67obg57OfV2Dnrhs1HtSdlY/i5fn7MU8=
+github.com/mark3labs/mcp-go v0.33.0 h1:naxhjnTIs/tyPZmWUZFuG0lDmdA6sUyYGGf3gsHvTCc=
-github.com/mark3labs/mcp-go v0.32.0/go.mod h1:rXqOudj/djTORU/ThxYx8fqEVj/5pvTuuebQ2RC7uk4=
+github.com/mark3labs/mcp-go v0.33.0/go.mod h1:rXqOudj/djTORU/ThxYx8fqEVj/5pvTuuebQ2RC7uk4=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6TULQc=

vendor/github.com/mark3labs/mcp-go/client/client.go

@@ -22,6 +22,7 @@ type Client struct {
 	requestID          atomic.Int64
 	clientCapabilities mcp.ClientCapabilities
 	serverCapabilities mcp.ServerCapabilities
+	samplingHandler    SamplingHandler
 }
 
 type ClientOption func(*Client)
@@ -33,6 +34,21 @@ func WithClientCapabilities(capabilities mcp.ClientCapabilities) ClientOption {
 	}
 }
 
+// WithSamplingHandler sets the sampling handler for the client.
+// When set, the client will declare sampling capability during initialization.
+func WithSamplingHandler(handler SamplingHandler) ClientOption {
+	return func(c *Client) {
+		c.samplingHandler = handler
+  }
+}
+
+// WithSession assumes a MCP Session has already been initialized
+func WithSession() ClientOption {
+	return func(c *Client) {
+		c.initialized = true
+	}
+}
+
 // NewClient creates a new MCP client with the given transport.
 // Usage:
 //
@@ -71,6 +87,12 @@ func (c *Client) Start(ctx context.Context) error {
 			handler(notification)
 		}
 	})
+
+	// Set up request handler for bidirectional communication (e.g., sampling)
+	if bidirectional, ok := c.transport.(transport.BidirectionalInterface); ok {
+		bidirectional.SetRequestHandler(c.handleIncomingRequest)
+	}
+
 	return nil
 }
 
@@ -127,6 +149,12 @@ func (c *Client) Initialize(
 	ctx context.Context,
 	request mcp.InitializeRequest,
 ) (*mcp.InitializeResult, error) {
+	// Merge client capabilities with sampling capability if handler is configured
+	capabilities := request.Params.Capabilities
+	if c.samplingHandler != nil {
+		capabilities.Sampling = &struct{}{}
+	}
+
 	// Ensure we send a params object with all required fields
 	params := struct {
 		ProtocolVersion string                 `json:"protocolVersion"`
@@ -135,7 +163,7 @@ func (c *Client) Initialize(
 	}{
 		ProtocolVersion: request.Params.ProtocolVersion,
 		ClientInfo:      request.Params.ClientInfo,
-		Capabilities:    request.Params.Capabilities, // Will be empty struct if not set
+		Capabilities:    capabilities,
 	}
 
 	response, err := c.sendRequest(ctx, "initialize", params)
@@ -398,6 +426,64 @@ func (c *Client) Complete(
 	return &result, nil
 }
 
+// handleIncomingRequest processes incoming requests from the server.
+// This is the main entry point for server-to-client requests like sampling.
+func (c *Client) handleIncomingRequest(ctx context.Context, request transport.JSONRPCRequest) (*transport.JSONRPCResponse, error) {
+	switch request.Method {
+	case string(mcp.MethodSamplingCreateMessage):
+		return c.handleSamplingRequestTransport(ctx, request)
+	default:
+		return nil, fmt.Errorf("unsupported request method: %s", request.Method)
+	}
+}
+
+// handleSamplingRequestTransport handles sampling requests at the transport level.
+func (c *Client) handleSamplingRequestTransport(ctx context.Context, request transport.JSONRPCRequest) (*transport.JSONRPCResponse, error) {
+	if c.samplingHandler == nil {
+		return nil, fmt.Errorf("no sampling handler configured")
+	}
+
+	// Parse the request parameters
+	var params mcp.CreateMessageParams
+	if request.Params != nil {
+		paramsBytes, err := json.Marshal(request.Params)
+		if err != nil {
+			return nil, fmt.Errorf("failed to marshal params: %w", err)
+		}
+		if err := json.Unmarshal(paramsBytes, &params); err != nil {
+			return nil, fmt.Errorf("failed to unmarshal params: %w", err)
+		}
+	}
+
+	// Create the MCP request
+	mcpRequest := mcp.CreateMessageRequest{
+		Request: mcp.Request{
+			Method: string(mcp.MethodSamplingCreateMessage),
+		},
+		CreateMessageParams: params,
+	}
+
+	// Call the sampling handler
+	result, err := c.samplingHandler.CreateMessage(ctx, mcpRequest)
+	if err != nil {
+		return nil, err
+	}
+
+	// Marshal the result
+	resultBytes, err := json.Marshal(result)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal result: %w", err)
+	}
+
+	// Create the transport response
+	response := &transport.JSONRPCResponse{
+		JSONRPC: mcp.JSONRPC_VERSION,
+		ID:      request.ID,
+		Result:  json.RawMessage(resultBytes),
+	}
+
+	return response, nil
+}
 func listByPage[T any](
 	ctx context.Context,
 	client *Client,
@@ -432,3 +518,17 @@ func (c *Client) GetServerCapabilities() mcp.ServerCapabilities {
 func (c *Client) GetClientCapabilities() mcp.ClientCapabilities {
 	return c.clientCapabilities
 }
+
+// GetSessionId returns the session ID of the transport.
+// If the transport does not support sessions, it returns an empty string.
+func (c *Client) GetSessionId() string {
+	if c.transport == nil {
+		return ""
+	}
+	return c.transport.GetSessionId()
+}
+
+// IsInitialized returns true if the client has been initialized.
+func (c *Client) IsInitialized() bool {
+	return c.initialized
+}

vendor/github.com/mark3labs/mcp-go/client/http.go

@@ -13,5 +13,10 @@ func NewStreamableHttpClient(baseURL string, options ...transport.StreamableHTTP
 	if err != nil {
 		return nil, fmt.Errorf("failed to create SSE transport: %w", err)
 	}
-	return NewClient(trans), nil
+	clientOptions := make([]ClientOption, 0)
+	sessionID := trans.GetSessionId()
+	if sessionID != "" {
+		clientOptions = append(clientOptions, WithSession())
+	}
+	return NewClient(trans, clientOptions...), nil
 }

vendor/github.com/mark3labs/mcp-go/client/sampling.go

@@ -0,0 +1,20 @@
+package client
+
+import (
+	"context"
+
+	"github.com/mark3labs/mcp-go/mcp"
+)
+
+// SamplingHandler defines the interface for handling sampling requests from servers.
+// Clients can implement this interface to provide LLM sampling capabilities to servers.
+type SamplingHandler interface {
+	// CreateMessage handles a sampling request from the server and returns the generated message.
+	// The implementation should:
+	// 1. Validate the request parameters
+	// 2. Optionally prompt the user for approval (human-in-the-loop)
+	// 3. Select an appropriate model based on preferences
+	// 4. Generate the response using the selected model
+	// 5. Return the result with model information and stop reason
+	CreateMessage(ctx context.Context, request mcp.CreateMessageRequest) (*mcp.CreateMessageResult, error)
+}

vendor/github.com/mark3labs/mcp-go/client/stdio.go

@@ -19,10 +19,26 @@ func NewStdioMCPClient(
 	env []string,
 	args ...string,
 ) (*Client, error) {
+	return NewStdioMCPClientWithOptions(command, env, args)
+}
 
-	stdioTransport := transport.NewStdio(command, env, args...)
+// NewStdioMCPClientWithOptions creates a new stdio-based MCP client that communicates with a subprocess.
-	err := stdioTransport.Start(context.Background())
+// It launches the specified command with given arguments and sets up stdin/stdout pipes for communication.
-	if err != nil {
+// Optional configuration functions can be provided to customize the transport before it starts,
+// such as setting a custom command function.
+//
+// NOTICE: NewStdioMCPClientWithOptions automatically starts the underlying transport.
+// Don't call the Start method manually.
+// This is for backward compatibility.
+func NewStdioMCPClientWithOptions(
+	command string,
+	env []string,
+	args []string,
+	opts ...transport.StdioOption,
+) (*Client, error) {
+	stdioTransport := transport.NewStdioWithOptions(command, env, args, opts...)
+
+	if err := stdioTransport.Start(context.Background()); err != nil {
 		return nil, fmt.Errorf("failed to start stdio transport: %w", err)
 	}
 

vendor/github.com/mark3labs/mcp-go/client/transport/inprocess.go

@@ -68,3 +68,7 @@ func (c *InProcessTransport) SetNotificationHandler(handler func(notification mc
 func (*InProcessTransport) Close() error {
 	return nil
 }
+
+func (c *InProcessTransport) GetSessionId() string {
+	return ""
+}

vendor/github.com/mark3labs/mcp-go/client/transport/interface.go

@@ -29,6 +29,22 @@ type Interface interface {
 
 	// Close the connection.
 	Close() error
+
+	// GetSessionId returns the session ID of the transport.
+	GetSessionId() string
+}
+
+// RequestHandler defines a function that handles incoming requests from the server.
+type RequestHandler func(ctx context.Context, request JSONRPCRequest) (*JSONRPCResponse, error)
+
+// BidirectionalInterface extends Interface to support incoming requests from the server.
+// This is used for features like sampling where the server can send requests to the client.
+type BidirectionalInterface interface {
+	Interface
+
+	// SetRequestHandler sets the handler for incoming requests from the server.
+	// The handler should process the request and return a response.
+	SetRequestHandler(handler RequestHandler)
 }
 
 type JSONRPCRequest struct {
@@ -41,10 +57,10 @@ type JSONRPCRequest struct {
 type JSONRPCResponse struct {
 	JSONRPC string          `json:"jsonrpc"`
 	ID      mcp.RequestId   `json:"id"`
-	Result  json.RawMessage `json:"result"`
+	Result  json.RawMessage `json:"result,omitempty"`
 	Error   *struct {
 		Code    int             `json:"code"`
 		Message string          `json:"message"`
 		Data    json.RawMessage `json:"data"`
-	} `json:"error"`
+	} `json:"error,omitempty"`
 }

vendor/github.com/mark3labs/mcp-go/client/transport/sse.go

@@ -428,6 +428,12 @@ func (c *SSE) Close() error {
 	return nil
 }
 
+// GetSessionId returns the session ID of the transport.
+// Since SSE does not maintain a session ID, it returns an empty string.
+func (c *SSE) GetSessionId() string {
+	return ""
+}
+
 // SendNotification sends a JSON-RPC notification to the server without expecting a response.
 func (c *SSE) SendNotification(ctx context.Context, notification mcp.JSONRPCNotification) error {
 	if c.endpoint == nil {

vendor/github.com/mark3labs/mcp-go/client/transport/stdio.go

@@ -23,6 +23,7 @@ type Stdio struct {
 	env     []string
 
 	cmd            *exec.Cmd
+	cmdFunc        CommandFunc
 	stdin          io.WriteCloser
 	stdout         *bufio.Reader
 	stderr         io.ReadCloser
@@ -31,6 +32,28 @@ type Stdio struct {
 	done           chan struct{}
 	onNotification func(mcp.JSONRPCNotification)
 	notifyMu       sync.RWMutex
+	onRequest      RequestHandler
+	requestMu      sync.RWMutex
+	ctx            context.Context
+	ctxMu          sync.RWMutex
+}
+
+// StdioOption defines a function that configures a Stdio transport instance.
+// Options can be used to customize the behavior of the transport before it starts,
+// such as setting a custom command function.
+type StdioOption func(*Stdio)
+
+// CommandFunc is a factory function that returns a custom exec.Cmd used to launch the MCP subprocess.
+// It can be used to apply sandboxing, custom environment control, working directories, etc.
+type CommandFunc func(ctx context.Context, command string, env []string, args []string) (*exec.Cmd, error)
+
+// WithCommandFunc sets a custom command factory function for the stdio transport.
+// The CommandFunc is responsible for constructing the exec.Cmd used to launch the subprocess,
+// allowing control over attributes like environment, working directory, and system-level sandboxing.
+func WithCommandFunc(f CommandFunc) StdioOption {
+	return func(s *Stdio) {
+		s.cmdFunc = f
+	}
 }
 
 // NewIO returns a new stdio-based transport using existing input, output, and
@@ -44,6 +67,7 @@ func NewIO(input io.Reader, output io.WriteCloser, logging io.ReadCloser) *Stdio
 
 		responses: make(map[string]chan *JSONRPCResponse),
 		done:      make(chan struct{}),
+		ctx:       context.Background(),
 	}
 }
 
@@ -55,20 +79,43 @@ func NewStdio(
 	env []string,
 	args ...string,
 ) *Stdio {
+	return NewStdioWithOptions(command, env, args)
+}
 
-	client := &Stdio{
+// NewStdioWithOptions creates a new stdio transport to communicate with a subprocess.
+// It launches the specified command with given arguments and sets up stdin/stdout pipes for communication.
+// Returns an error if the subprocess cannot be started or the pipes cannot be created.
+// Optional configuration functions can be provided to customize the transport before it starts,
+// such as setting a custom command factory.
+func NewStdioWithOptions(
+	command string,
+	env []string,
+	args []string,
+	opts ...StdioOption,
+) *Stdio {
+	s := &Stdio{
 		command: command,
 		args:    args,
 		env:     env,
 
 		responses: make(map[string]chan *JSONRPCResponse),
 		done:      make(chan struct{}),
+		ctx:       context.Background(),
 	}
 
-	return client
+	for _, opt := range opts {
+		opt(s)
+	}
+
+	return s
 }
 
 func (c *Stdio) Start(ctx context.Context) error {
+	// Store the context for use in request handling
+	c.ctxMu.Lock()
+	c.ctx = ctx
+	c.ctxMu.Unlock()
+
 	if err := c.spawnCommand(ctx); err != nil {
 		return err
 	}
@@ -83,18 +130,25 @@ func (c *Stdio) Start(ctx context.Context) error {
 	return nil
 }
 
-// spawnCommand spawns a new process running c.command.
+// spawnCommand spawns a new process running the configured command, args, and env.
+// If an (optional) cmdFunc custom command factory function was configured, it will be used to construct the subprocess;
+// otherwise, the default behavior uses exec.CommandContext with the merged environment.
+// Initializes stdin, stdout, and stderr pipes for JSON-RPC communication.
 func (c *Stdio) spawnCommand(ctx context.Context) error {
 	if c.command == "" {
 		return nil
 	}
 
-	cmd := exec.CommandContext(ctx, c.command, c.args...)
+	var cmd *exec.Cmd
+	var err error
 
-	mergedEnv := os.Environ()
+	// Standard behavior if no command func present.
-	mergedEnv = append(mergedEnv, c.env...)
+	if c.cmdFunc == nil {
-
+		cmd = exec.CommandContext(ctx, c.command, c.args...)
-	cmd.Env = mergedEnv
+		cmd.Env = append(os.Environ(), c.env...)
+	} else if cmd, err = c.cmdFunc(ctx, c.command, c.env, c.args); err != nil {
+		return err
+	}
 
 	stdin, err := cmd.StdinPipe()
 	if err != nil {
@@ -148,6 +202,12 @@ func (c *Stdio) Close() error {
 	return nil
 }
 
+// GetSessionId returns the session ID of the transport.
+// Since stdio does not maintain a session ID, it returns an empty string.
+func (c *Stdio) GetSessionId() string {
+	return ""
+}
+
 // SetNotificationHandler sets the handler function to be called when a notification is received.
 // Only one handler can be set at a time; setting a new one replaces the previous handler.
 func (c *Stdio) SetNotificationHandler(
@@ -158,6 +218,14 @@ func (c *Stdio) SetNotificationHandler(
 	c.onNotification = handler
 }
 
+// SetRequestHandler sets the handler function to be called when a request is received from the server.
+// This enables bidirectional communication for features like sampling.
+func (c *Stdio) SetRequestHandler(handler RequestHandler) {
+	c.requestMu.Lock()
+	defer c.requestMu.Unlock()
+	c.onRequest = handler
+}
+
 // readResponses continuously reads and processes responses from the server's stdout.
 // It handles both responses to requests and notifications, routing them appropriately.
 // Runs until the done channel is closed or an error occurs reading from stdout.
@@ -175,13 +243,18 @@ func (c *Stdio) readResponses() {
 				return
 			}
 
-			var baseMessage JSONRPCResponse
+			// First try to parse as a generic message to check for ID field
+			var baseMessage struct {
+				JSONRPC string         `json:"jsonrpc"`
+				ID      *mcp.RequestId `json:"id,omitempty"`
+				Method  string         `json:"method,omitempty"`
+			}
 			if err := json.Unmarshal([]byte(line), &baseMessage); err != nil {
 				continue
 			}
 
-			// Handle notification
+			// If it has a method but no ID, it's a notification
-			if baseMessage.ID.IsNil() {
+			if baseMessage.Method != "" && baseMessage.ID == nil {
 				var notification mcp.JSONRPCNotification
 				if err := json.Unmarshal([]byte(line), &notification); err != nil {
 					continue
@@ -194,15 +267,30 @@ func (c *Stdio) readResponses() {
 				continue
 			}
 
+			// If it has a method and an ID, it's an incoming request
+			if baseMessage.Method != "" && baseMessage.ID != nil {
+				var request JSONRPCRequest
+				if err := json.Unmarshal([]byte(line), &request); err == nil {
+					c.handleIncomingRequest(request)
+					continue
+				}
+			}
+
+			// Otherwise, it's a response to our request
+			var response JSONRPCResponse
+			if err := json.Unmarshal([]byte(line), &response); err != nil {
+				continue
+			}
+
 			// Create string key for map lookup
-			idKey := baseMessage.ID.String()
+			idKey := response.ID.String()
 
 			c.mu.RLock()
 			ch, exists := c.responses[idKey]
 			c.mu.RUnlock()
 
 			if exists {
-				ch <- &baseMessage
+				ch <- &response
 				c.mu.Lock()
 				delete(c.responses, idKey)
 				c.mu.Unlock()
@@ -281,6 +369,96 @@ func (c *Stdio) SendNotification(
 	return nil
 }
 
+// handleIncomingRequest processes incoming requests from the server.
+// It calls the registered request handler and sends the response back to the server.
+func (c *Stdio) handleIncomingRequest(request JSONRPCRequest) {
+	c.requestMu.RLock()
+	handler := c.onRequest
+	c.requestMu.RUnlock()
+
+	if handler == nil {
+		// Send error response if no handler is configured
+		errorResponse := JSONRPCResponse{
+			JSONRPC: mcp.JSONRPC_VERSION,
+			ID:      request.ID,
+			Error: &struct {
+				Code    int             `json:"code"`
+				Message string          `json:"message"`
+				Data    json.RawMessage `json:"data"`
+			}{
+				Code:    mcp.METHOD_NOT_FOUND,
+				Message: "No request handler configured",
+			},
+		}
+		c.sendResponse(errorResponse)
+		return
+	}
+
+	// Handle the request in a goroutine to avoid blocking
+	go func() {
+		c.ctxMu.RLock()
+		ctx := c.ctx
+		c.ctxMu.RUnlock()
+
+		// Check if context is already cancelled before processing
+		select {
+		case <-ctx.Done():
+			errorResponse := JSONRPCResponse{
+				JSONRPC: mcp.JSONRPC_VERSION,
+				ID:      request.ID,
+				Error: &struct {
+					Code    int             `json:"code"`
+					Message string          `json:"message"`
+					Data    json.RawMessage `json:"data"`
+				}{
+					Code:    mcp.INTERNAL_ERROR,
+					Message: ctx.Err().Error(),
+				},
+			}
+			c.sendResponse(errorResponse)
+			return
+		default:
+		}
+
+		response, err := handler(ctx, request)
+
+		if err != nil {
+			errorResponse := JSONRPCResponse{
+				JSONRPC: mcp.JSONRPC_VERSION,
+				ID:      request.ID,
+				Error: &struct {
+					Code    int             `json:"code"`
+					Message string          `json:"message"`
+					Data    json.RawMessage `json:"data"`
+				}{
+					Code:    mcp.INTERNAL_ERROR,
+					Message: err.Error(),
+				},
+			}
+			c.sendResponse(errorResponse)
+			return
+		}
+
+		if response != nil {
+			c.sendResponse(*response)
+		}
+	}()
+}
+
+// sendResponse sends a response back to the server.
+func (c *Stdio) sendResponse(response JSONRPCResponse) {
+	responseBytes, err := json.Marshal(response)
+	if err != nil {
+		fmt.Printf("Error marshaling response: %v\n", err)
+		return
+	}
+	responseBytes = append(responseBytes, '\n')
+
+	if _, err := c.stdin.Write(responseBytes); err != nil {
+		fmt.Printf("Error writing response: %v\n", err)
+	}
+}
+
 // Stderr returns a reader for the stderr output of the subprocess.
 // This can be used to capture error messages or logs from the subprocess.
 func (c *Stdio) Stderr() io.Reader {

vendor/github.com/mark3labs/mcp-go/client/transport/streamable_http.go

@@ -17,10 +17,24 @@ import (
 	"time"
 
 	"github.com/mark3labs/mcp-go/mcp"
+	"github.com/mark3labs/mcp-go/util"
 )
 
 type StreamableHTTPCOption func(*StreamableHTTP)
 
+// WithContinuousListening enables receiving server-to-client notifications when no request is in flight.
+// In particular, if you want to receive global notifications from the server (like ToolListChangedNotification),
+// you should enable this option.
+//
+// It will establish a standalone long-live GET HTTP connection to the server.
+// https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#listening-for-messages-from-the-server
+// NOTICE: Even enabled, the server may not support this feature.
+func WithContinuousListening() StreamableHTTPCOption {
+	return func(sc *StreamableHTTP) {
+		sc.getListeningEnabled = true
+	}
+}
+
 // WithHTTPClient sets a custom HTTP client on the StreamableHTTP transport.
 func WithHTTPBasicClient(client *http.Client) StreamableHTTPCOption {
 	return func(sc *StreamableHTTP) {
@@ -54,6 +68,19 @@ func WithHTTPOAuth(config OAuthConfig) StreamableHTTPCOption {
 	}
 }
 
+func WithLogger(logger util.Logger) StreamableHTTPCOption {
+	return func(sc *StreamableHTTP) {
+		sc.logger = logger
+	}
+}
+
+// WithSession creates a client with a pre-configured session
+func WithSession(sessionID string) StreamableHTTPCOption {
+	return func(sc *StreamableHTTP) {
+		sc.sessionID.Store(sessionID)
+	}
+}
+
 // StreamableHTTP implements Streamable HTTP transport.
 //
 // It transmits JSON-RPC messages over individual HTTP requests. One message per request.
@@ -64,19 +91,22 @@ func WithHTTPOAuth(config OAuthConfig) StreamableHTTPCOption {
 //
 // The current implementation does not support the following features:
 //   - batching
-//   - continuously listening for server notifications when no request is in flight
-//     (https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#listening-for-messages-from-the-server)
 //   - resuming stream
 //     (https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#resumability-and-redelivery)
 //   - server -> client request
 type StreamableHTTP struct {
-	serverURL  *url.URL
+	serverURL           *url.URL
-	httpClient *http.Client
+	httpClient          *http.Client
-	headers    map[string]string
+	headers             map[string]string
-	headerFunc HTTPHeaderFunc
+	headerFunc          HTTPHeaderFunc
+	logger              util.Logger
+	getListeningEnabled bool
 
 	sessionID atomic.Value // string
 
+	initialized     chan struct{}
+	initializedOnce sync.Once
+
 	notificationHandler func(mcp.JSONRPCNotification)
 	notifyMu            sync.RWMutex
 
@@ -95,15 +125,19 @@ func NewStreamableHTTP(serverURL string, options ...StreamableHTTPCOption) (*Str
 	}
 
 	smc := &StreamableHTTP{
-		serverURL:  parsedURL,
+		serverURL:   parsedURL,
-		httpClient: &http.Client{},
+		httpClient:  &http.Client{},
-		headers:    make(map[string]string),
+		headers:     make(map[string]string),
-		closed:     make(chan struct{}),
+		closed:      make(chan struct{}),
+		logger:      util.DefaultLogger(),
+		initialized: make(chan struct{}),
 	}
 	smc.sessionID.Store("") // set initial value to simplify later usage
 
 	for _, opt := range options {
-		opt(smc)
+		if opt != nil {
+			opt(smc)
+		}
 	}
 
 	// If OAuth is configured, set the base URL for metadata discovery
@@ -118,7 +152,20 @@ func NewStreamableHTTP(serverURL string, options ...StreamableHTTPCOption) (*Str
 
 // Start initiates the HTTP connection to the server.
 func (c *StreamableHTTP) Start(ctx context.Context) error {
-	// For Streamable HTTP, we don't need to establish a persistent connection
+	// For Streamable HTTP, we don't need to establish a persistent connection by default
+	if c.getListeningEnabled {
+		go func() {
+			select {
+			case <-c.initialized:
+				ctx, cancel := c.contextAwareOfClientClose(ctx)
+				defer cancel()
+				c.listenForever(ctx)
+			case <-c.closed:
+				return
+			}
+		}()
+	}
+
 	return nil
 }
 
@@ -142,13 +189,13 @@ func (c *StreamableHTTP) Close() error {
 			defer cancel()
 			req, err := http.NewRequestWithContext(ctx, http.MethodDelete, c.serverURL.String(), nil)
 			if err != nil {
-				fmt.Printf("failed to create close request\n: %v", err)
+				c.logger.Errorf("failed to create close request: %v", err)
 				return
 			}
 			req.Header.Set(headerKeySessionID, sessionId)
 			res, err := c.httpClient.Do(req)
 			if err != nil {
-				fmt.Printf("failed to send close request\n: %v", err)
+				c.logger.Errorf("failed to send close request: %v", err)
 				return
 			}
 			res.Body.Close()
@@ -185,37 +232,103 @@ func (c *StreamableHTTP) SendRequest(
 	request JSONRPCRequest,
 ) (*JSONRPCResponse, error) {
 
-	// Create a combined context that could be canceled when the client is closed
-	newCtx, cancel := context.WithCancel(ctx)
-	defer cancel()
-	go func() {
-		select {
-		case <-c.closed:
-			cancel()
-		case <-newCtx.Done():
-			// The original context was canceled, no need to do anything
-		}
-	}()
-	ctx = newCtx
-
 	// Marshal request
 	requestBody, err := json.Marshal(request)
 	if err != nil {
 		return nil, fmt.Errorf("failed to marshal request: %w", err)
 	}
 
+	ctx, cancel := c.contextAwareOfClientClose(ctx)
+	defer cancel()
+
+	resp, err := c.sendHTTP(ctx, http.MethodPost, bytes.NewReader(requestBody), "application/json, text/event-stream")
+	if err != nil {
+		if errors.Is(err, ErrSessionTerminated) && request.Method == string(mcp.MethodInitialize) {
+			// If the request is initialize, should not return a SessionTerminated error
+			// It should be a genuine endpoint-routing issue.
+			// ( Fall through to return StatusCode checking. )
+		} else {
+			return nil, fmt.Errorf("failed to send request: %w", err)
+		}
+	}
+	defer resp.Body.Close()
+
+	// Check if we got an error response
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted {
+
+		// Handle OAuth unauthorized error
+		if resp.StatusCode == http.StatusUnauthorized && c.oauthHandler != nil {
+			return nil, &OAuthAuthorizationRequiredError{
+				Handler: c.oauthHandler,
+			}
+		}
+
+		// handle error response
+		var errResponse JSONRPCResponse
+		body, _ := io.ReadAll(resp.Body)
+		if err := json.Unmarshal(body, &errResponse); err == nil {
+			return &errResponse, nil
+		}
+		return nil, fmt.Errorf("request failed with status %d: %s", resp.StatusCode, body)
+	}
+
+	if request.Method == string(mcp.MethodInitialize) {
+		// saved the received session ID in the response
+		// empty session ID is allowed
+		if sessionID := resp.Header.Get(headerKeySessionID); sessionID != "" {
+			c.sessionID.Store(sessionID)
+		}
+
+		c.initializedOnce.Do(func() {
+			close(c.initialized)
+		})
+	}
+
+	// Handle different response types
+	mediaType, _, _ := mime.ParseMediaType(resp.Header.Get("Content-Type"))
+	switch mediaType {
+	case "application/json":
+		// Single response
+		var response JSONRPCResponse
+		if err := json.NewDecoder(resp.Body).Decode(&response); err != nil {
+			return nil, fmt.Errorf("failed to decode response: %w", err)
+		}
+
+		// should not be a notification
+		if response.ID.IsNil() {
+			return nil, fmt.Errorf("response should contain RPC id: %v", response)
+		}
+
+		return &response, nil
+
+	case "text/event-stream":
+		// Server is using SSE for streaming responses
+		return c.handleSSEResponse(ctx, resp.Body, false)
+
+	default:
+		return nil, fmt.Errorf("unexpected content type: %s", resp.Header.Get("Content-Type"))
+	}
+}
+
+func (c *StreamableHTTP) sendHTTP(
+	ctx context.Context,
+	method string,
+	body io.Reader,
+	acceptType string,
+) (resp *http.Response, err error) {
+
 	// Create HTTP request
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.serverURL.String(), bytes.NewReader(requestBody))
+	req, err := http.NewRequestWithContext(ctx, method, c.serverURL.String(), body)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create request: %w", err)
 	}
 
 	// Set headers
 	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("Accept", "application/json, text/event-stream")
+	req.Header.Set("Accept", acceptType)
-	sessionID := c.sessionID.Load()
+	sessionID := c.sessionID.Load().(string)
 	if sessionID != "" {
-		req.Header.Set(headerKeySessionID, sessionID.(string))
+		req.Header.Set(headerKeySessionID, sessionID)
 	}
 	for k, v := range c.headers {
 		req.Header.Set(k, v)
@@ -243,73 +356,24 @@ func (c *StreamableHTTP) SendRequest(
 	}
 
 	// Send request
-	resp, err := c.httpClient.Do(req)
+	resp, err = c.httpClient.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("failed to send request: %w", err)
 	}
-	defer resp.Body.Close()
 
-	// Check if we got an error response
+	// universal handling for session terminated
-	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted {
+	if resp.StatusCode == http.StatusNotFound {
-		// handle session closed
+		c.sessionID.CompareAndSwap(sessionID, "")
-		if resp.StatusCode == http.StatusNotFound {
+		return nil, ErrSessionTerminated
-			c.sessionID.CompareAndSwap(sessionID, "")
-			return nil, fmt.Errorf("session terminated (404). need to re-initialize")
-		}
-
-		// Handle OAuth unauthorized error
-		if resp.StatusCode == http.StatusUnauthorized && c.oauthHandler != nil {
-			return nil, &OAuthAuthorizationRequiredError{
-				Handler: c.oauthHandler,
-			}
-		}
-
-		// handle error response
-		var errResponse JSONRPCResponse
-		body, _ := io.ReadAll(resp.Body)
-		if err := json.Unmarshal(body, &errResponse); err == nil {
-			return &errResponse, nil
-		}
-		return nil, fmt.Errorf("request failed with status %d: %s", resp.StatusCode, body)
 	}
 
-	if request.Method == string(mcp.MethodInitialize) {
+	return resp, nil
-		// saved the received session ID in the response
-		// empty session ID is allowed
-		if sessionID := resp.Header.Get(headerKeySessionID); sessionID != "" {
-			c.sessionID.Store(sessionID)
-		}
-	}
-
-	// Handle different response types
-	mediaType, _, _ := mime.ParseMediaType(resp.Header.Get("Content-Type"))
-	switch mediaType {
-	case "application/json":
-		// Single response
-		var response JSONRPCResponse
-		if err := json.NewDecoder(resp.Body).Decode(&response); err != nil {
-			return nil, fmt.Errorf("failed to decode response: %w", err)
-		}
-
-		// should not be a notification
-		if response.ID.IsNil() {
-			return nil, fmt.Errorf("response should contain RPC id: %v", response)
-		}
-
-		return &response, nil
-
-	case "text/event-stream":
-		// Server is using SSE for streaming responses
-		return c.handleSSEResponse(ctx, resp.Body)
-
-	default:
-		return nil, fmt.Errorf("unexpected content type: %s", resp.Header.Get("Content-Type"))
-	}
 }
 
 // handleSSEResponse processes an SSE stream for a specific request.
 // It returns the final result for the request once received, or an error.
-func (c *StreamableHTTP) handleSSEResponse(ctx context.Context, reader io.ReadCloser) (*JSONRPCResponse, error) {
+// If ignoreResponse is true, it won't return when a response messge is received. This is for continuous listening.
+func (c *StreamableHTTP) handleSSEResponse(ctx context.Context, reader io.ReadCloser, ignoreResponse bool) (*JSONRPCResponse, error) {
 
 	// Create a channel for this specific request
 	responseChan := make(chan *JSONRPCResponse, 1)
@@ -328,7 +392,7 @@ func (c *StreamableHTTP) handleSSEResponse(ctx context.Context, reader io.ReadCl
 
 			var message JSONRPCResponse
 			if err := json.Unmarshal([]byte(data), &message); err != nil {
-				fmt.Printf("failed to unmarshal message: %v\n", err)
+				c.logger.Errorf("failed to unmarshal message: %v", err)
 				return
 			}
 
@@ -336,7 +400,7 @@ func (c *StreamableHTTP) handleSSEResponse(ctx context.Context, reader io.ReadCl
 			if message.ID.IsNil() {
 				var notification mcp.JSONRPCNotification
 				if err := json.Unmarshal([]byte(data), &notification); err != nil {
-					fmt.Printf("failed to unmarshal notification: %v\n", err)
+					c.logger.Errorf("failed to unmarshal notification: %v", err)
 					return
 				}
 				c.notifyMu.RLock()
@@ -347,7 +411,9 @@ func (c *StreamableHTTP) handleSSEResponse(ctx context.Context, reader io.ReadCl
 				return
 			}
 
-			responseChan <- &message
+			if !ignoreResponse {
+				responseChan <- &message
+			}
 		})
 	}()
 
@@ -393,7 +459,7 @@ func (c *StreamableHTTP) readSSE(ctx context.Context, reader io.ReadCloser, hand
 				case <-ctx.Done():
 					return
 				default:
-					fmt.Printf("SSE stream error: %v\n", err)
+					c.logger.Errorf("SSE stream error: %v", err)
 					return
 				}
 			}
@@ -432,44 +498,10 @@ func (c *StreamableHTTP) SendNotification(ctx context.Context, notification mcp.
 	}
 
 	// Create HTTP request
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.serverURL.String(), bytes.NewReader(requestBody))
+	ctx, cancel := c.contextAwareOfClientClose(ctx)
-	if err != nil {
+	defer cancel()
-		return fmt.Errorf("failed to create request: %w", err)
-	}
 
-	// Set headers
+	resp, err := c.sendHTTP(ctx, http.MethodPost, bytes.NewReader(requestBody), "application/json, text/event-stream")
-	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("Accept", "application/json, text/event-stream")
-	if sessionID := c.sessionID.Load(); sessionID != "" {
-		req.Header.Set(headerKeySessionID, sessionID.(string))
-	}
-	for k, v := range c.headers {
-		req.Header.Set(k, v)
-	}
-
-	// Add OAuth authorization if configured
-	if c.oauthHandler != nil {
-		authHeader, err := c.oauthHandler.GetAuthorizationHeader(ctx)
-		if err != nil {
-			// If we get an authorization error, return a specific error that can be handled by the client
-			if errors.Is(err, ErrOAuthAuthorizationRequired) {
-				return &OAuthAuthorizationRequiredError{
-					Handler: c.oauthHandler,
-				}
-			}
-			return fmt.Errorf("failed to get authorization header: %w", err)
-		}
-		req.Header.Set("Authorization", authHeader)
-	}
-
-	if c.headerFunc != nil {
-		for k, v := range c.headerFunc(ctx) {
-			req.Header.Set(k, v)
-		}
-	}
-
-	// Send request
-	resp, err := c.httpClient.Do(req)
 	if err != nil {
 		return fmt.Errorf("failed to send request: %w", err)
 	}
@@ -513,3 +545,84 @@ func (c *StreamableHTTP) GetOAuthHandler() *OAuthHandler {
 func (c *StreamableHTTP) IsOAuthEnabled() bool {
 	return c.oauthHandler != nil
 }
+
+func (c *StreamableHTTP) listenForever(ctx context.Context) {
+	c.logger.Infof("listening to server forever")
+	for {
+		err := c.createGETConnectionToServer(ctx)
+		if errors.Is(err, ErrGetMethodNotAllowed) {
+			// server does not support listening
+			c.logger.Errorf("server does not support listening")
+			return
+		}
+
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
+
+		if err != nil {
+			c.logger.Errorf("failed to listen to server. retry in 1 second: %v", err)
+		}
+		time.Sleep(retryInterval)
+	}
+}
+
+var (
+	ErrSessionTerminated   = fmt.Errorf("session terminated (404). need to re-initialize")
+	ErrGetMethodNotAllowed = fmt.Errorf("GET method not allowed")
+
+	retryInterval = 1 * time.Second // a variable is convenient for testing
+)
+
+func (c *StreamableHTTP) createGETConnectionToServer(ctx context.Context) error {
+
+	resp, err := c.sendHTTP(ctx, http.MethodGet, nil, "text/event-stream")
+	if err != nil {
+		return fmt.Errorf("failed to send request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	// Check if we got an error response
+	if resp.StatusCode == http.StatusMethodNotAllowed {
+		return ErrGetMethodNotAllowed
+	}
+
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted {
+		body, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("request failed with status %d: %s", resp.StatusCode, body)
+	}
+
+	// handle SSE response
+	contentType := resp.Header.Get("Content-Type")
+	if contentType != "text/event-stream" {
+		return fmt.Errorf("unexpected content type: %s", contentType)
+	}
+
+	// When ignoreResponse is true, the function will never return expect context is done.
+	// NOTICE: Due to the ambiguity of the specification, other SDKs may use the GET connection to transfer the response
+	// messages. To be more compatible, we should handle this response, however, as the transport layer is message-based,
+	// currently, there is no convenient way to handle this response.
+	// So we ignore the response here. It's not a bug, but may be not compatible with other SDKs.
+	_, err = c.handleSSEResponse(ctx, resp.Body, true)
+	if err != nil {
+		return fmt.Errorf("failed to handle SSE response: %w", err)
+	}
+
+	return nil
+}
+
+func (c *StreamableHTTP) contextAwareOfClientClose(ctx context.Context) (context.Context, context.CancelFunc) {
+	newCtx, cancel := context.WithCancel(ctx)
+	go func() {
+		select {
+		case <-c.closed:
+			cancel()
+		case <-newCtx.Done():
+			// The original context was canceled
+			cancel()
+		}
+	}()
+	return newCtx, cancel
+}

vendor/github.com/mark3labs/mcp-go/mcp/tools.go

@@ -945,7 +945,20 @@ func PropertyNames(schema map[string]any) PropertyOption {
 	}
 }
 
-// Items defines the schema for array items
+// Items defines the schema for array items.
+// Accepts any schema definition for maximum flexibility.
+//
+// Example:
+//
+//	Items(map[string]any{
+//	    "type": "object",
+//	    "properties": map[string]any{
+//	        "name": map[string]any{"type": "string"},
+//	        "age": map[string]any{"type": "number"},
+//	    },
+//	})
+//
+// For simple types, use ItemsString(), ItemsNumber(), ItemsBoolean() instead.
 func Items(schema any) PropertyOption {
 	return func(schemaMap map[string]any) {
 		schemaMap["items"] = schema
@@ -972,3 +985,94 @@ func UniqueItems(unique bool) PropertyOption {
 		schema["uniqueItems"] = unique
 	}
 }
+
+// WithStringItems configures an array's items to be of type string.
+//
+// Supported options: Description(), DefaultString(), Enum(), MaxLength(), MinLength(), Pattern()
+// Note: Options like Required() are not valid for item schemas and will be ignored.
+//
+// Examples:
+//
+//	mcp.WithArray("tags", mcp.WithStringItems())
+//	mcp.WithArray("colors", mcp.WithStringItems(mcp.Enum("red", "green", "blue")))
+//	mcp.WithArray("names", mcp.WithStringItems(mcp.MinLength(1), mcp.MaxLength(50)))
+//
+// Limitations: Only supports simple string arrays. Use Items() for complex objects.
+func WithStringItems(opts ...PropertyOption) PropertyOption {
+	return func(schema map[string]any) {
+		itemSchema := map[string]any{
+			"type": "string",
+		}
+
+		for _, opt := range opts {
+			opt(itemSchema)
+		}
+
+		schema["items"] = itemSchema
+	}
+}
+
+// WithStringEnumItems configures an array's items to be of type string with a specified enum.
+// Example:
+//
+//	mcp.WithArray("priority", mcp.WithStringEnumItems([]string{"low", "medium", "high"}))
+//
+// Limitations: Only supports string enums. Use WithStringItems(Enum(...)) for more flexibility.
+func WithStringEnumItems(values []string) PropertyOption {
+	return func(schema map[string]any) {
+		schema["items"] = map[string]any{
+			"type": "string",
+			"enum": values,
+		}
+	}
+}
+
+// WithNumberItems configures an array's items to be of type number.
+//
+// Supported options: Description(), DefaultNumber(), Min(), Max(), MultipleOf()
+// Note: Options like Required() are not valid for item schemas and will be ignored.
+//
+// Examples:
+//
+//	mcp.WithArray("scores", mcp.WithNumberItems(mcp.Min(0), mcp.Max(100)))
+//	mcp.WithArray("prices", mcp.WithNumberItems(mcp.Min(0)))
+//
+// Limitations: Only supports simple number arrays. Use Items() for complex objects.
+func WithNumberItems(opts ...PropertyOption) PropertyOption {
+	return func(schema map[string]any) {
+		itemSchema := map[string]any{
+			"type": "number",
+		}
+
+		for _, opt := range opts {
+			opt(itemSchema)
+		}
+
+		schema["items"] = itemSchema
+	}
+}
+
+// WithBooleanItems configures an array's items to be of type boolean.
+//
+// Supported options: Description(), DefaultBool()
+// Note: Options like Required() are not valid for item schemas and will be ignored.
+//
+// Examples:
+//
+//	mcp.WithArray("flags", mcp.WithBooleanItems())
+//	mcp.WithArray("permissions", mcp.WithBooleanItems(mcp.Description("User permissions")))
+//
+// Limitations: Only supports simple boolean arrays. Use Items() for complex objects.
+func WithBooleanItems(opts ...PropertyOption) PropertyOption {
+	return func(schema map[string]any) {
+		itemSchema := map[string]any{
+			"type": "boolean",
+		}
+
+		for _, opt := range opts {
+			opt(itemSchema)
+		}
+
+		schema["items"] = itemSchema
+	}
+}

vendor/github.com/mark3labs/mcp-go/mcp/types.go

@@ -763,6 +763,11 @@ const (
 
 /* Sampling */
 
+const (
+	// MethodSamplingCreateMessage allows servers to request LLM completions from clients
+	MethodSamplingCreateMessage MCPMethod = "sampling/createMessage"
+)
+
 // CreateMessageRequest is a request from the server to sample an LLM via the
 // client. The client has full discretion over which model to select. The client
 // should also inform the user before beginning sampling, to allow them to inspect
@@ -865,6 +870,22 @@ type AudioContent struct {
 
 func (AudioContent) isContent() {}
 
+// ResourceLink represents a link to a resource that the client can access.
+type ResourceLink struct {
+	Annotated
+	Type string `json:"type"` // Must be "resource_link"
+	// The URI of the resource.
+	URI string `json:"uri"`
+	// The name of the resource.
+	Name string `json:"name"`
+	// The description of the resource.
+	Description string `json:"description"`
+	// The MIME type of the resource.
+	MIMEType string `json:"mimeType"`
+}
+
+func (ResourceLink) isContent() {}
+
 // EmbeddedResource represents the contents of a resource, embedded into a prompt or tool call result.
 //
 // It is up to the client how best to render embedded resources for the

vendor/github.com/mark3labs/mcp-go/mcp/utils.go

@@ -222,6 +222,17 @@ func NewAudioContent(data, mimeType string) AudioContent {
 	}
 }
 
+// Helper function to create a new ResourceLink
+func NewResourceLink(uri, name, description, mimeType string) ResourceLink {
+	return ResourceLink{
+		Type:        "resource_link",
+		URI:         uri,
+		Name:        name,
+		Description: description,
+		MIMEType:    mimeType,
+	}
+}
+
 // Helper function to create a new EmbeddedResource
 func NewEmbeddedResource(resource ResourceContents) EmbeddedResource {
 	return EmbeddedResource{
@@ -476,6 +487,16 @@ func ParseContent(contentMap map[string]any) (Content, error) {
 		}
 		return NewAudioContent(data, mimeType), nil
 
+	case "resource_link":
+		uri := ExtractString(contentMap, "uri")
+		name := ExtractString(contentMap, "name")
+		description := ExtractString(contentMap, "description")
+		mimeType := ExtractString(contentMap, "mimeType")
+		if uri == "" || name == "" {
+			return nil, fmt.Errorf("resource_link uri or name is missing")
+		}
+		return NewResourceLink(uri, name, description, mimeType), nil
+
 	case "resource":
 		resourceMap := ExtractMap(contentMap, "resource")
 		if resourceMap == nil {

vendor/github.com/mark3labs/mcp-go/server/sampling.go

@@ -0,0 +1,37 @@
+package server
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/mark3labs/mcp-go/mcp"
+)
+
+// EnableSampling enables sampling capabilities for the server.
+// This allows the server to send sampling requests to clients that support it.
+func (s *MCPServer) EnableSampling() {
+	s.capabilitiesMu.Lock()
+	defer s.capabilitiesMu.Unlock()
+}
+
+// RequestSampling sends a sampling request to the client.
+// The client must have declared sampling capability during initialization.
+func (s *MCPServer) RequestSampling(ctx context.Context, request mcp.CreateMessageRequest) (*mcp.CreateMessageResult, error) {
+	session := ClientSessionFromContext(ctx)
+	if session == nil {
+		return nil, fmt.Errorf("no active session")
+	}
+
+	// Check if the session supports sampling requests
+	if samplingSession, ok := session.(SessionWithSampling); ok {
+		return samplingSession.RequestSampling(ctx, request)
+	}
+
+	return nil, fmt.Errorf("session does not support sampling")
+}
+
+// SessionWithSampling extends ClientSession to support sampling requests.
+type SessionWithSampling interface {
+	ClientSession
+	RequestSampling(ctx context.Context, request mcp.CreateMessageRequest) (*mcp.CreateMessageResult, error)
+}

vendor/github.com/mark3labs/mcp-go/server/stdio.go

@@ -9,6 +9,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
+	"sync"
 	"sync/atomic"
 	"syscall"
 
@@ -51,10 +52,21 @@ func WithStdioContextFunc(fn StdioContextFunc) StdioOption {
 
 // stdioSession is a static client session, since stdio has only one client.
 type stdioSession struct {
-	notifications chan mcp.JSONRPCNotification
+	notifications   chan mcp.JSONRPCNotification
-	initialized   atomic.Bool
+	initialized     atomic.Bool
-	loggingLevel  atomic.Value
+	loggingLevel    atomic.Value
-	clientInfo    atomic.Value // stores session-specific client info
+	clientInfo      atomic.Value                     // stores session-specific client info
+	writer          io.Writer                        // for sending requests to client
+	requestID       atomic.Int64                     // for generating unique request IDs
+	mu              sync.RWMutex                     // protects writer
+	pendingRequests map[int64]chan *samplingResponse // for tracking pending sampling requests
+	pendingMu       sync.RWMutex                     // protects pendingRequests
+}
+
+// samplingResponse represents a response to a sampling request
+type samplingResponse struct {
+	result *mcp.CreateMessageResult
+	err    error
 }
 
 func (s *stdioSession) SessionID() string {
@@ -100,14 +112,86 @@ func (s *stdioSession) GetLogLevel() mcp.LoggingLevel {
 	return level.(mcp.LoggingLevel)
 }
 
+// RequestSampling sends a sampling request to the client and waits for the response.
+func (s *stdioSession) RequestSampling(ctx context.Context, request mcp.CreateMessageRequest) (*mcp.CreateMessageResult, error) {
+	s.mu.RLock()
+	writer := s.writer
+	s.mu.RUnlock()
+
+	if writer == nil {
+		return nil, fmt.Errorf("no writer available for sending requests")
+	}
+
+	// Generate a unique request ID
+	id := s.requestID.Add(1)
+
+	// Create a response channel for this request
+	responseChan := make(chan *samplingResponse, 1)
+	s.pendingMu.Lock()
+	s.pendingRequests[id] = responseChan
+	s.pendingMu.Unlock()
+
+	// Cleanup function to remove the pending request
+	cleanup := func() {
+		s.pendingMu.Lock()
+		delete(s.pendingRequests, id)
+		s.pendingMu.Unlock()
+	}
+	defer cleanup()
+
+	// Create the JSON-RPC request
+	jsonRPCRequest := struct {
+		JSONRPC string                  `json:"jsonrpc"`
+		ID      int64                   `json:"id"`
+		Method  string                  `json:"method"`
+		Params  mcp.CreateMessageParams `json:"params"`
+	}{
+		JSONRPC: mcp.JSONRPC_VERSION,
+		ID:      id,
+		Method:  string(mcp.MethodSamplingCreateMessage),
+		Params:  request.CreateMessageParams,
+	}
+
+	// Marshal and send the request
+	requestBytes, err := json.Marshal(jsonRPCRequest)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal sampling request: %w", err)
+	}
+	requestBytes = append(requestBytes, '\n')
+
+	if _, err := writer.Write(requestBytes); err != nil {
+		return nil, fmt.Errorf("failed to write sampling request: %w", err)
+	}
+
+	// Wait for the response or context cancellation
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case response := <-responseChan:
+		if response.err != nil {
+			return nil, response.err
+		}
+		return response.result, nil
+	}
+}
+
+// SetWriter sets the writer for sending requests to the client.
+func (s *stdioSession) SetWriter(writer io.Writer) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.writer = writer
+}
+
 var (
 	_ ClientSession         = (*stdioSession)(nil)
 	_ SessionWithLogging    = (*stdioSession)(nil)
 	_ SessionWithClientInfo = (*stdioSession)(nil)
+	_ SessionWithSampling   = (*stdioSession)(nil)
 )
 
 var stdioSessionInstance = stdioSession{
-	notifications: make(chan mcp.JSONRPCNotification, 100),
+	notifications:   make(chan mcp.JSONRPCNotification, 100),
+	pendingRequests: make(map[int64]chan *samplingResponse),
 }
 
 // NewStdioServer creates a new stdio server wrapper around an MCPServer.
@@ -224,6 +308,9 @@ func (s *StdioServer) Listen(
 	defer s.server.UnregisterSession(ctx, stdioSessionInstance.SessionID())
 	ctx = s.server.WithContext(ctx, &stdioSessionInstance)
 
+	// Set the writer for sending requests to the client
+	stdioSessionInstance.SetWriter(stdout)
+
 	// Add in any custom context.
 	if s.contextFunc != nil {
 		ctx = s.contextFunc(ctx)
@@ -256,7 +343,29 @@ func (s *StdioServer) processMessage(
 		return s.writeResponse(response, writer)
 	}
 
-	// Handle the message using the wrapped server
+	// Check if this is a response to a sampling request
+	if s.handleSamplingResponse(rawMessage) {
+		return nil
+	}
+
+	// Check if this is a tool call that might need sampling (and thus should be processed concurrently)
+	var baseMessage struct {
+		Method string `json:"method"`
+	}
+	if json.Unmarshal(rawMessage, &baseMessage) == nil && baseMessage.Method == "tools/call" {
+		// Process tool calls concurrently to avoid blocking on sampling requests
+		go func() {
+			response := s.server.HandleMessage(ctx, rawMessage)
+			if response != nil {
+				if err := s.writeResponse(response, writer); err != nil {
+					s.errLogger.Printf("Error writing tool response: %v", err)
+				}
+			}
+		}()
+		return nil
+	}
+
+	// Handle other messages synchronously
 	response := s.server.HandleMessage(ctx, rawMessage)
 
 	// Only write response if there is one (not for notifications)
@@ -269,6 +378,65 @@ func (s *StdioServer) processMessage(
 	return nil
 }
 
+// handleSamplingResponse checks if the message is a response to a sampling request
+// and routes it to the appropriate pending request channel.
+func (s *StdioServer) handleSamplingResponse(rawMessage json.RawMessage) bool {
+	return stdioSessionInstance.handleSamplingResponse(rawMessage)
+}
+
+// handleSamplingResponse handles incoming sampling responses for this session
+func (s *stdioSession) handleSamplingResponse(rawMessage json.RawMessage) bool {
+	// Try to parse as a JSON-RPC response
+	var response struct {
+		JSONRPC string          `json:"jsonrpc"`
+		ID      json.Number     `json:"id"`
+		Result  json.RawMessage `json:"result,omitempty"`
+		Error   *struct {
+			Code    int    `json:"code"`
+			Message string `json:"message"`
+		} `json:"error,omitempty"`
+	}
+
+	if err := json.Unmarshal(rawMessage, &response); err != nil {
+		return false
+	}
+	// Parse the ID as int64
+	idInt64, err := response.ID.Int64()
+	if err != nil || (response.Result == nil && response.Error == nil) {
+		return false
+	}
+
+	// Look for a pending request with this ID
+	s.pendingMu.RLock()
+	responseChan, exists := s.pendingRequests[idInt64]
+	s.pendingMu.RUnlock()
+
+	if !exists {
+		return false
+	} // Parse and send the response
+	samplingResp := &samplingResponse{}
+
+	if response.Error != nil {
+		samplingResp.err = fmt.Errorf("sampling request failed: %s", response.Error.Message)
+	} else {
+		var result mcp.CreateMessageResult
+		if err := json.Unmarshal(response.Result, &result); err != nil {
+			samplingResp.err = fmt.Errorf("failed to unmarshal sampling response: %w", err)
+		} else {
+			samplingResp.result = &result
+		}
+	}
+
+	// Send the response (non-blocking)
+	select {
+	case responseChan <- samplingResp:
+	default:
+		// Channel is full or closed, ignore
+	}
+
+	return true
+}
+
 // writeResponse marshals and writes a JSON-RPC response message followed by a newline.
 // Returns an error if marshaling or writing fails.
 func (s *StdioServer) writeResponse(

vendor/github.com/mark3labs/mcp-go/server/streamable_http.go

@@ -40,7 +40,9 @@ func WithEndpointPath(endpointPath string) StreamableHTTPOption {
 // to StatelessSessionIdManager.
 func WithStateLess(stateLess bool) StreamableHTTPOption {
 	return func(s *StreamableHTTPServer) {
-		s.sessionIdManager = &StatelessSessionIdManager{}
+		if stateLess {
+			s.sessionIdManager = &StatelessSessionIdManager{}
+		}
 	}
 }
 
@@ -374,7 +376,7 @@ func (s *StreamableHTTPServer) handleGet(w http.ResponseWriter, r *http.Request)
 	w.Header().Set("Content-Type", "text/event-stream")
 	w.Header().Set("Cache-Control", "no-cache")
 	w.Header().Set("Connection", "keep-alive")
-	w.WriteHeader(http.StatusAccepted)
+	w.WriteHeader(http.StatusOK)
 
 	flusher, ok := w.(http.Flusher)
 	if !ok {

vendor/modules.txt

@@ -403,7 +403,7 @@ github.com/kylelemons/godebug/pretty
 # github.com/lucasb-eyer/go-colorful v1.2.0
 ## explicit; go 1.12
 github.com/lucasb-eyer/go-colorful
-# github.com/mark3labs/mcp-go v0.32.0
+# github.com/mark3labs/mcp-go v0.33.0
 ## explicit; go 1.23
 github.com/mark3labs/mcp-go/client
 github.com/mark3labs/mcp-go/client/transport