graph edge[start]-[Chain[0]_chat_model]: start node's output type[*schema.Message] and end node's input type[[]*schema.Message] mismatch exit status 1

[pdxrlj]

// 获取工具信息, 用于绑定到 ChatModel
	toolInfos := make([]*schema.ToolInfo, 0, len(todoTools))
	for _, todoTool := range todoTools {
		info, err := todoTool.Info(context.Background())
		if err != nil {
			log.Fatal(err)
		}
		toolInfos = append(toolInfos, info)
	}

	// 将 tools 绑定到 ChatModel
	err = chatModel.BindTools(toolInfos)
	if err != nil {
		log.Fatal(err)
	}
	// 创建 tools 节点
	todoToolsNode, err := compose.NewToolNode(context.Background(),
		&compose.ToolsNodeConfig{
			Tools: todoTools,
		})
	if err != nil {
		log.Fatal(err)
	}

	// 构建完整的处理链
	chain := compose.NewChain[*schema.Message, []*schema.Message]()
	chain.
		AppendChatModel(chatModel, compose.WithNodeName("chat_model")).
		AppendToolsNode(todoToolsNode, compose.WithNodeName("tools"))

	// 编译并运行 chain
	agent, err := chain.Compile(context.Background())
	if err != nil {
		log.Fatal(err)
	}

	// 运行示例
	resp, err := agent.Invoke(context.Background(), &schema.Message{
		Content: "使用add_todo工具帮我创建一个明天下午3点截止的待办事项：准备Eino项目演示文稿",
	})
	if err != nil {
		log.Fatal(err)
	}

	// 输出结果
	for _, msg := range resp {
		fmt.Println(msg.Content)
	}

工具使用

func (t *Todo) CreateToDoList(ctx context.Context, input *AddTodoInput) (*AddTodoOutput, error) {
	haveTable := HaveTable(DB())
	if !haveTable {
		err := Migrate(DB())
		if err != nil {
			return nil, err
		}
	}
	output := &AddTodoOutput{
		Content:  input.Content,
		StartAt:  input.StartAt,
		Detailed: input.Detailed,
	}

	if err := DB().Create(&Todo{
		Content:  input.Content,
		StartAt:  int64(input.StartAt),
		Detailed: int64(input.Detailed),
	}).Error; err != nil {
		return output, err
	}
	return output, nil
}

func (t *Todo) MarshalOutput(_ context.Context, req any) (string, error) {
	out, ok := req.(*AddTodoOutput)
	if !ok {
		return "", fmt.Errorf("invalid input type")
	}

	return fmt.Sprintf("Todo item added: %v", out), nil
}

输出

2025/01/17 13:27:52 graph edge[start]-[Chain[0]_chat_model]: start node's output type[*schema.Message] and end node's input type[[]*schema.Message] mismatch
exit status 1

[shentongmartin]

Is this code from eino-examples? If so, try pulling the newest main branch. It contains the fix for this.