update godoc and data format

Author: yuehaii

client/client.go

@@ -481,6 +481,7 @@ func (c *Client) Complete(
 	return &result, nil
 }
 
+// RootListChanges sends a roots list-changed notification to the server.
 func (c *Client) RootListChanges(
 	ctx context.Context,
 ) error {
@@ -602,7 +603,7 @@ func (c *Client) handleListRootsRequestTransport(ctx context.Context, request tr
 	}
 
 	// Create the transport response
-	response := transport.NewJSONRPCResultResponse(request.ID, resultBytes)
+	response := transport.NewJSONRPCResultResponse(request.ID, json.RawMessage(resultBytes))
 
 	return response, nil
 }

examples/roots_client/main.go

@@ -14,7 +14,7 @@ import (
 )
 
 // MockRootsHandler implements client.RootsHandler for demonstration.
-// In a real implementation, this would integrate with an actual LLM API.
+// In a real implementation, this would enumerate workspace/project roots.
 type MockRootsHandler struct{}
 
 func (h *MockRootsHandler) ListRoots(ctx context.Context, request mcp.ListRootsRequest) (*mcp.ListRootsResult, error) {
@@ -115,7 +115,7 @@ func main() {
 	// call server tool
 	request := mcp.CallToolRequest{}
 	request.Params.Name = "roots"
-	request.Params.Arguments = "{\"testonly\": \"yes\"}"
+	request.Params.Arguments = map[string]any{"testonly": "yes"}
 	result, err := mcpClient.CallTool(ctx, request)
 	if err != nil {
 		log.Fatalf("failed to call tool roots: %v", err)
@@ -126,7 +126,7 @@ func main() {
 				resultStr += fmt.Sprintf("%s\n", textContent.Text)
 			}
 		}
-		fmt.Printf("client call tool result: %s", resultStr)
+		fmt.Printf("client call tool result: %s\n", resultStr)
 	}
 
 	// mock the root change

examples/roots_http_client/main.go

@@ -14,7 +14,7 @@ import (
 )
 
 // MockRootsHandler implements client.RootsHandler for demonstration.
-// In a real implementation, this would integrate with an actual LLM API.
+// In a real implementation, this would enumerate workspace/project roots.
 type MockRootsHandler struct{}
 
 func (h *MockRootsHandler) ListRoots(ctx context.Context, request mcp.ListRootsRequest) (*mcp.ListRootsResult, error) {
@@ -33,9 +33,9 @@ func (h *MockRootsHandler) ListRoots(ctx context.Context, request mcp.ListRootsR
 	return result, nil
 }
 
-// main starts a mock MCP roots client that communicates with a MCP server over http.
-// client will call server tool to get the root list. in server tool hander, it will send the list root request to client.
-// shuts down the client gracefully on SIGINT or SIGTERM.
+// main starts a mock MCP roots client over HTTP.
+// The server tool triggers a roots/list request on the client.
+// The client shuts down gracefully on SIGINT or SIGTERM.
 func main() {
 	// Create roots handler
 	rootsHandler := &MockRootsHandler{}
@@ -97,7 +97,7 @@ func main() {
 	// call server tool
 	request := mcp.CallToolRequest{}
 	request.Params.Name = "roots"
-	request.Params.Arguments = "{\"testonly\": \"yes\"}"
+	request.Params.Arguments = map[string]any{"testonly": "yes"}
 	result, err := mcpClient.CallTool(ctx, request)
 	if err != nil {
 		log.Fatalf("failed to call tool roots: %v", err)
@@ -108,7 +108,7 @@ func main() {
 				resultStr += fmt.Sprintf("%s\n", textContent.Text)
 			}
 		}
-		fmt.Printf("client call tool result: %s", resultStr)
+		fmt.Printf("client call tool result: %s\n", resultStr)
 	}
 
 	// Keep the client running (in a real app, you'd have your main application logic here)

examples/roots_server/main.go

@@ -11,7 +11,7 @@ import (
 
 // handleNotification handles JSON-RPC notifications by printing the notification method to standard output.
 func handleNotification(ctx context.Context, notification mcp.JSONRPCNotification) {
-	fmt.Printf("notification received: %v", notification.Notification.Method)
+	fmt.Printf("notification received: %v\n", notification.Notification.Method)
 }
 
 // main sets up and runs an MCP stdio server named "roots-stdio-server" with tool and roots capabilities.
@@ -27,9 +27,8 @@ func main() {
 	// Create MCP server with roots capability
 	mcpServer := server.NewMCPServer("roots-stdio-server", "1.0.0", opts...)
 
-	// Add list root list change notification
+	// Register roots list-change notification handler
 	mcpServer.AddNotificationHandler(mcp.MethodNotificationRootsListChanged, handleNotification)
-	mcpServer.EnableSampling()
 
 	// Add a simple tool to test roots list
 	mcpServer.AddTool(mcp.Tool{
@@ -59,7 +58,15 @@ func main() {
 			}, nil
 
 		} else {
-			return nil, err
+			return &mcp.CallToolResult{
+				Content: []mcp.Content{
+					mcp.TextContent{
+						Type: "text",
+						Text: fmt.Sprintf("Fail to list roots: %v", err),
+					},
+				},
+				IsError: true,
+			}, nil
 		}
 	})
 

mcp/types.go

@@ -74,7 +74,7 @@ const (
 	MethodNotificationPromptsListChanged = "notifications/prompts/list_changed"
 
 	// MethodNotificationToolsListChanged notifies when the list of available tools changes.
-	// https://modelcontextprotocol.io/specification/2025-06-18/client/roots#root-list-changes
+	// https://modelcontextprotocol.io/specification/2025-06-18/server/tools#list-changed-notification
 	MethodNotificationToolsListChanged = "notifications/tools/list_changed"
 
 	// MethodNotificationRootsListChanged notifies when the list of available roots changes.