使用supervisor Agent创建的adk.Runner，内部通过tool调用sub agent后ToolCall.Function.Arguments格式错误

[luweiwei]

Describe the bug

使用supervisor Agent创建的adk.Runner，内部通过tool调用sub agent后ToolCall.Function.Arguments格式错误

Version:
v0.7.32

错误信息

panic: [NodeRunError] error generating request: error convert messages: error parsing JSON to object: invalid character 'M' looking for beginning of value
        ------------------------
        node path: [node_1, ChatModel]

goroutine 1 [running]:
main.main()
        xxx/main.go:82 +0x704
exit status 2

测试代码

package main

import (
	"ai-worker/utils"
	"bufio"
	"context"
	"fmt"
	"os"

	"github.com/cloudwego/eino-ext/components/model/ollama"
	"github.com/cloudwego/eino/adk"
	"github.com/cloudwego/eino/adk/prebuilt/supervisor"
	"github.com/cloudwego/eino/components/model"
	"github.com/cloudwego/eino/schema"
)

type transferParams struct {
	AgentName string `json:"agent_name"`
}

func main() {
	ctx := context.Background()

	model, err := newChatModel(ctx)
	if err != nil {
		panic(err)
	}

	mainAgent, err := adk.NewChatModelAgent(ctx, &adk.ChatModelAgentConfig{
		Name:        "MainAgent",
		Description: "An agent that can do anything",
		Model:       model,
	})
	if err != nil {
		panic(err)
	}

	subAgent, err := adk.NewChatModelAgent(ctx, &adk.ChatModelAgentConfig{
		Name:        "SubAgent",
		Description: "An agent that can do anything",
		Model:       model,
	})
	if err != nil {
		panic(err)
	}

	agent, err := supervisor.New(ctx, &supervisor.Config{
		Supervisor: mainAgent,
		SubAgents:  []adk.Agent{subAgent},
	})
	if err != nil {
		panic(err)
	}

	runner := adk.NewRunner(ctx, adk.RunnerConfig{
		Agent: agent,
	})

	messages := []*schema.Message{}

	for {
		input, err := getUserInput(ctx)
		if err != nil {
			panic(err)
		}
		if input == "" {
			continue
		}
		if input == "/bye" {
			break
		}
		messages = append(messages, schema.UserMessage(input))

		iter := runner.Run(ctx, messages)
		for {
			event, ok := iter.Next()
			if !ok {
				break
			}
			if event.Err != nil {
				utils.PrintAny(messages)
				panic(event.Err)
			}
			if event.Output != nil && event.Output.MessageOutput != nil {
				mo := event.Output.MessageOutput
				var msg *schema.Message
				if mo.IsStreaming {
					var printedRole bool
					for {
						chunk, err := mo.MessageStream.Recv()
						if err != nil {
							break
						}
						if !printedRole {
							fmt.Println(mo.Message.Role + ":")
							printedRole = true
						}
						fmt.Print(chunk)
					}
					msg, err = mo.GetMessage()
					if err != nil {
						panic(err)
					}
				} else {
					msg, err = mo.GetMessage()
					if err != nil {
						panic(err)
					}
					fmt.Println(mo.Message.Role + ":")
					fmt.Println(msg.Content)
				}

				// 转换ToolCall.Function.Arguments的格式，不转换就会报解析错误
				// if msg.Role == schema.Assistant {
				// 	for i, ts := range msg.ToolCalls {
				// 		if ts.Function.Name == "transfer_to_agent" {
				// 			tp := transferParams{}
				// 			err := json.Unmarshal([]byte(ts.Function.Arguments), &tp)
				// 			if err != nil {
				// 				msg.ToolCalls[i].Function.Arguments = fmt.Sprintf("{\"agent_name\":\"%s\"}", ts.Function.Arguments)
				// 			}
				// 		}
				// 	}
				// }

				messages = append(messages, msg)
			}
		}
	}

	utils.PrintAny(messages)

}

func newChatModel(ctx context.Context) (model.ToolCallingChatModel, error) {
	return ollama.NewChatModel(ctx, &ollama.ChatModelConfig{
		BaseURL: "http://localhost:11434",
		Model:   "ministral-3:3b-instruct-2512-q4_K_M",
	})
}

func getUserInput(ctx context.Context) (string, error) {
	scanner := bufio.NewScanner(os.Stdin)
	fmt.Print("user:")
	if scanner.Scan() {
		return scanner.Text(), nil
	}

	if err := scanner.Err(); err != nil {
		return "", err
	}
	return "", context.DeadlineExceeded
}

传递的essages

[{"role":"user","content":"呼叫SubAgent"},{"role":"assistant","content":"","tool_calls":[{"id":"","type":"function","function":{"name":"transfer_to_agent","arguments":"{\"agent_name\":\"SubAgent\"}"}}],"response_meta":{"finish_reason":"stop","usage":{"prompt_tokens":147,"prompt_token_details":{"cached_tokens":0},"completion_tokens":14,"total_tokens":161,"completion_token_details":{}}}},{"role":"tool","content":"successfully transferred to agent [SubAgent]","tool_name":"transfer_to_agent"},{"role":"assistant","content":"理解！现在我将以**SubAgent**的身份开始处理任务。请告诉我下一步的具体要求或问题，我将专注于提供准确、详细的回复。\n\n**当前状态**：\n- 已切换至**SubAgent**模式。\n- 可处理实时2026年2月10日（或相关时间）的信息。\n- 无法访问互联网或图片/音频等多模态功能。\n\n请确认您的需求，例如：\n- 需要查询最新数据（如股票、天气、新闻等）？\n- 需要解决具体问题（如计算、逻辑推理）？\n- 需要翻译或文本分析？","response_meta":{"finish_reason":"stop","usage":{"prompt_tokens":608,"prompt_token_details":{"cached_tokens":0},"completion_tokens":186,"total_tokens":794,"completion_token_details":{}}}},{"role":"assistant","content":"","tool_calls":[{"id":"ac565622-cfbd-4437-8486-3cec3f8be949","type":"","function":{"name":"transfer_to_agent","arguments":"MainAgent"}}]},{"role":"tool","content":"successfully transferred to agent [MainAgent]","tool_call_id":"ac565622-cfbd-4437-8486-3cec3f8be949","tool_name":"transfer_to_agent"},{"role":"assistant","content":"我已将问题转交给**MainAgent**处理。请等待其回复！","response_meta":{"finish_reason":"stop","usage":{"prompt_tokens":414,"prompt_token_details":{"cached_tokens":0},"completion_tokens":22,"total_tokens":436,"completion_token_details":{}}}},{"role":"user","content":"你好"}]