Add mcp-client-go
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amikai
parent
e0c5614acc
commit
c0601f5c41
1 changed files with 331 additions and 0 deletions
277
mcp-client-go/main.go
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277
mcp-client-go/main.go
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package main
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import (
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"bufio"
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"context"
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"encoding/json"
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"fmt"
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"log"
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"os"
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"os/exec"
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"strings"
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"github.com/anthropics/anthropic-sdk-go"
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"github.com/anthropics/anthropic-sdk-go/option"
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"github.com/joho/godotenv"
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"github.com/modelcontextprotocol/go-sdk/mcp"
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)
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var model anthropic.Model = anthropic.ModelClaudeSonnet4_5_20250929
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type MCPClient struct {
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anthropic *anthropic.Client
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session *mcp.ClientSession
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tools []anthropic.ToolUnionParam
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}
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func NewMCPClient() (*MCPClient, error) {
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// Load .env file
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if err := godotenv.Load(); err != nil {
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return nil, fmt.Errorf("failed to load .env file: %w", err)
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}
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apiKey := os.Getenv("ANTHROPIC_API_KEY")
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if apiKey == "" {
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return nil, fmt.Errorf("ANTHROPIC_API_KEY environment variable not set")
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}
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client := anthropic.NewClient(option.WithAPIKey(apiKey))
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return &MCPClient{
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anthropic: &client,
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}, nil
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}
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func (c *MCPClient) ConnectToServer(ctx context.Context, serverArgs []string) error {
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if len(serverArgs) == 0 {
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return fmt.Errorf("no server command provided")
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}
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// Create command to spawn server process
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cmd := exec.CommandContext(ctx, serverArgs[0], serverArgs[1:]...)
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// Create MCP client
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client := mcp.NewClient(
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&mcp.Implementation{
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Name: "mcp-client-go",
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Version: "0.1.0",
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},
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nil,
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)
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// Connect using CommandTransport
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transport := &mcp.CommandTransport{
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Command: cmd,
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}
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session, err := client.Connect(ctx, transport, nil)
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if err != nil {
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return fmt.Errorf("failed to connect to server: %w", err)
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}
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c.session = session
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// List available tools
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toolsResult, err := session.ListTools(ctx, &mcp.ListToolsParams{})
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if err != nil {
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return fmt.Errorf("failed to list tools: %w", err)
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}
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var toolNames []string
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// Convert MCP tools to Anthropic tool format
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for _, tool := range toolsResult.Tools {
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toolNames = append(toolNames, tool.Name)
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anthropicTool, err := mcpToolToAnthropicTool(tool)
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if err != nil {
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return fmt.Errorf("failed to convert mcp tool to anthropic tool: %w", err)
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}
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c.tools = append(c.tools, anthropicTool)
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}
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fmt.Printf("Connected to server with tools: %v\n", toolNames)
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return nil
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}
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func mcpToolToAnthropicTool(tool *mcp.Tool) (anthropic.ToolUnionParam, error) {
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var zeroTool anthropic.ToolUnionParam
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schemaJSON, err := json.Marshal(tool.InputSchema)
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if err != nil {
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return zeroTool, fmt.Errorf("failed to marshal input schema of mcp tool: %w", err)
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}
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var schema anthropic.ToolInputSchemaParam
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err = json.Unmarshal(schemaJSON, &schema)
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if err != nil {
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return zeroTool, fmt.Errorf("failed to unmarshal to anthropic input schema: %w", err)
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}
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toolParam := anthropic.ToolParam{
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Name: tool.Name,
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Description: anthropic.String(tool.Description),
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InputSchema: schema,
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}
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return anthropic.ToolUnionParam{
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OfTool: &toolParam,
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}, nil
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}
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func (c *MCPClient) ProcessQuery(ctx context.Context, query string) (string, error) {
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if c.session == nil {
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return "", fmt.Errorf("client is not connected to any server")
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}
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messages := []anthropic.MessageParam{
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anthropic.NewUserMessage(anthropic.NewTextBlock(query)),
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}
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// Initial Claude API call with tools
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response, err := c.anthropic.Messages.New(ctx, anthropic.MessageNewParams{
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Model: model,
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MaxTokens: 1024,
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Messages: messages,
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Tools: c.tools,
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})
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if err != nil {
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return "", fmt.Errorf("anthropic API request failed: %w", err)
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}
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var toolUseBlocks []anthropic.ToolUseBlock
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var finalText []string
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for _, block := range response.Content {
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switch b := block.AsAny().(type) {
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case anthropic.TextBlock:
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finalText = append(finalText, b.Text)
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case anthropic.ToolUseBlock:
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toolUseBlocks = append(toolUseBlocks, b)
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}
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}
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if len(toolUseBlocks) == 0 {
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return strings.Join(finalText, "\n"), nil
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}
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// Append assistant's response to message history
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messages = append(messages, response.ToParam())
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// Execute each tool call and collect responses
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var anthropicToolResults []anthropic.ContentBlockParamUnion
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for _, toolUseBlock := range toolUseBlocks {
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// Add information about the tool call to final text
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finalText = append(finalText, fmt.Sprintf("[Calling tool %s with args %s]", toolUseBlock.Name, string(toolUseBlock.Input)))
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// Call the MCP server tool
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mcpToolResult, err := c.session.CallTool(ctx, &mcp.CallToolParams{
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Name: toolUseBlock.Name,
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Arguments: toolUseBlock.Input,
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})
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if err != nil {
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return "", fmt.Errorf("tool call %s failed: %w", toolUseBlock.Name, err)
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}
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// Serialize tool result
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resultJSON, err := json.Marshal(mcpToolResult)
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if err != nil {
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return "", fmt.Errorf("failed to serialize tool result: %w", err)
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}
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anthropicToolResults = append(anthropicToolResults, anthropic.NewToolResultBlock(
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toolUseBlock.ID,
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string(resultJSON),
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false,
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))
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}
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// Append tool responses to message history
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messages = append(messages, anthropic.NewUserMessage(anthropicToolResults...))
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// Make another API call with tool results
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response, err = c.anthropic.Messages.New(ctx, anthropic.MessageNewParams{
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Model: anthropic.ModelClaude3_7SonnetLatest,
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MaxTokens: 1024,
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Messages: messages,
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})
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if err != nil {
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return "", fmt.Errorf("anthropic API request with tool results failed: %w", err)
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}
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// Collect text from final response
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for _, block := range response.Content {
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switch b := block.AsAny().(type) {
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case anthropic.TextBlock:
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finalText = append(finalText, b.Text)
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}
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}
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return strings.Join(finalText, "\n"), nil
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}
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func (c *MCPClient) ChatLoop(ctx context.Context) error {
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fmt.Println("\nMCP Client Started!")
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fmt.Println("Type your queries or 'quit' to exit.")
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scanner := bufio.NewScanner(os.Stdin)
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for {
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fmt.Print("\nQuery: ")
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if !scanner.Scan() {
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break // EOF
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}
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query := strings.TrimSpace(scanner.Text())
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if strings.EqualFold(query, "quit") {
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break
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}
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if query == "" {
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continue
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}
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response, err := c.ProcessQuery(ctx, query)
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if err != nil {
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fmt.Printf("\nError: %v\n", err)
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continue
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}
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fmt.Printf("\n%s\n", response)
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}
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return scanner.Err()
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}
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func (c *MCPClient) Cleanup() error {
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if c.session != nil {
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if err := c.session.Close(); err != nil {
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return fmt.Errorf("failed to close session: %w", err)
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}
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c.session = nil
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}
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return nil
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}
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func main() {
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if len(os.Args) < 2 {
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fmt.Fprintln(os.Stderr, "Usage: go run main.go <server_script_or_binary> [args...]")
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os.Exit(1)
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}
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serverArgs := os.Args[1:]
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client, err := NewMCPClient()
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if err != nil {
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log.Fatalf("Failed to create MCP client: %v", err)
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}
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ctx := context.Background()
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if err := client.ConnectToServer(ctx, serverArgs); err != nil {
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log.Fatalf("Failed to connect to MCP server: %v", err)
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}
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if err := client.ChatLoop(ctx); err != nil {
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log.Printf("ChatLoop error: %v", err)
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}
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if err := client.Cleanup(); err != nil {
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log.Printf("Cleanup error: %v", err)
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}
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}
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