update comments

client/client.go

@@ -1,3 +1,4 @@
+// Package client provides MCP (Model Control Protocol) client implementations.
 package client
 
 import (

client/sse.go

@@ -17,6 +17,9 @@ import (
 	"github.com/mark3labs/mcp-go/mcp"
 )
 
+// SSEMCPClient implements the MCPClient interface using Server-Sent Events (SSE).
+// It maintains a persistent HTTP connection to receive server-pushed events
+// while sending requests over regular HTTP POST calls.
 type SSEMCPClient struct {
 	baseURL       *url.URL
 	endpoint      *url.URL

client/stdio.go

@@ -13,6 +13,8 @@ import (
 	"github.com/mark3labs/mcp-go/mcp"
 )
 
+// StdioMCPClient implements the MCPClient interface using stdio communication.
+// It launches a subprocess and communicates with it via standard input/output streams.
 type StdioMCPClient struct {
 	cmd           *exec.Cmd
 	stdin         io.WriteCloser

server/server.go

@@ -1,3 +1,4 @@
+// Package server provides MCP (Model Control Protocol) server implementations.
 package server
 
 import (
@@ -7,6 +8,24 @@ import (
 	"github.com/mark3labs/mcp-go/mcp"
 )
 
+// ServerOption is a function that configures an MCPServer.
+type ServerOption func(*MCPServer)
+
+// ResourceHandlerFunc is a function that returns resource contents.
+type ResourceHandlerFunc func() ([]interface{}, error)
+
+// ResourceTemplateHandlerFunc is a function that returns a resource template.
+type ResourceTemplateHandlerFunc func() (mcp.ResourceTemplate, error)
+
+// PromptHandlerFunc handles prompt requests with given arguments.
+type PromptHandlerFunc func(arguments map[string]string) (*mcp.GetPromptResult, error)
+
+// ToolHandlerFunc handles tool calls with given arguments.
+type ToolHandlerFunc func(arguments map[string]interface{}) (*mcp.CallToolResult, error)
+
+// NotificationHandlerFunc handles incoming notifications.
+type NotificationHandlerFunc func(notification mcp.JSONRPCNotification)
+
 type MCPServer struct {
 	name              string
 	version           string
@@ -34,16 +53,6 @@ type promptCapabilities struct {
 	listChanged bool
 }
 
-type ServerOption func(*MCPServer)
-
-type ResourceHandlerFunc func() ([]interface{}, error)
-type ResourceTemplateHandlerFunc func() (mcp.ResourceTemplate, error)
-
-type PromptHandlerFunc func(arguments map[string]string) (*mcp.GetPromptResult, error)
-
-type ToolHandlerFunc func(arguments map[string]interface{}) (*mcp.CallToolResult, error)
-type NotificationHandlerFunc func(notification mcp.JSONRPCNotification)
-
 func WithResourceCapabilities(subscribe, listChanged bool) ServerOption {
 	return func(s *MCPServer) {
 		s.capabilities.resources = &resourceCapabilities{
@@ -61,7 +70,6 @@ func WithPromptCapabilities(listChanged bool) ServerOption {
 	}
 }
 
-
 func WithLogging() ServerOption {
 	return func(s *MCPServer) {
 		s.capabilities.logging = true

server/sse.go

@@ -9,15 +9,19 @@ import (
 	"sync"
 
 	"github.com/google/uuid"
+	"github.com/mark3labs/mcp-go/mcp"
 )
 
+// SSEServer implements a Server-Sent Events (SSE) based MCP server.
+// It provides real-time communication capabilities over HTTP using the SSE protocol.
 type SSEServer struct {
 	server   *MCPServer
 	baseURL  string
 	sessions sync.Map
 	srv      *http.Server
 }
 
+// sseSession represents an active SSE connection.
 type sseSession struct {
 	writer  http.ResponseWriter
 	flusher http.Flusher
@@ -123,27 +127,27 @@ func (s *SSEServer) handleSSE(w http.ResponseWriter, r *http.Request) {
 
 func (s *SSEServer) handleMessage(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodPost {
-		s.writeJSONRPCError(w, nil, -32600, "Method not allowed")
+		s.writeJSONRPCError(w, nil, mcp.INVALID_REQUEST, "Method not allowed")
 		return
 	}
 
 	sessionID := r.URL.Query().Get("sessionId")
 	if sessionID == "" {
-		s.writeJSONRPCError(w, nil, -32602, "Missing sessionId")
+		s.writeJSONRPCError(w, nil, mcp.INVALID_PARAMS, "Missing sessionId")
 		return
 	}
 
 	sessionI, ok := s.sessions.Load(sessionID)
 	if !ok {
-		s.writeJSONRPCError(w, nil, -32602, "Invalid session ID")
+		s.writeJSONRPCError(w, nil, mcp.INVALID_PARAMS, "Invalid session ID")
 		return
 	}
 	session := sessionI.(*sseSession)
 
 	// Parse message as raw JSON
 	var rawMessage json.RawMessage
 	if err := json.NewDecoder(r.Body).Decode(&rawMessage); err != nil {
-		s.writeJSONRPCError(w, nil, -32700, "Parse error")
+		s.writeJSONRPCError(w, nil, mcp.PARSE_ERROR, "Parse error")
 		return
 	}
 

server/stdio.go

@@ -15,6 +15,9 @@ import (
 )
 
 // StdioServer wraps a MCPServer and handles stdio communication
+// StdioServer wraps a MCPServer and handles stdio communication.
+// It provides a simple way to create command-line MCP servers that
+// communicate via standard input/output streams.
 type StdioServer struct {
 	server    *MCPServer
 	errLogger *log.Logger