「Cloudflare Agents と AI SDK でAIエージェントを作ってみた」 というタイトルでDevelopersIO Sapporo 2025 に登壇しました #devio2025

			
			npm create cloudflare@latest agents-starter -- --template=cloudflare/agents-starter

		

			
			import { AIChatAgent } from "agents/ai-chat-agent";
import { streamText } from "ai";

export class Chat extends AIChatAgent<Env> {
  async onChatMessage(
    onFinish: StreamTextOnFinishCallback<ToolSet>
  ) {
    const stream = createUIMessageStream({
      execute: async ({ writer }) => {
        const result = streamText({
          system: `You are a helpful assistant that can do various tasks`,
          messages: convertToModelMessages(this.messages),
          model,
          tools: allTools,
          onFinish: onFinish as unknown as StreamTextOnFinishCallback<
            typeof allTools
          >,
          stopWhen: stepCountIs(10)
        });
        writer.merge(result.toUIMessageStream());
      }
    });

    return createUIMessageStreamResponse({ stream });
  }
}

		

			
			 const agent = useAgent({
    agent: "Chat"
  });

		

			
			  const {
    messages: agentMessages,
    addToolResult,
    clearHistory,
    status,
    sendMessage,
    stop
  } = useAgentChat<unknown, UIMessage<{ createdAt: string }>>({
    agent
  });

		

			
			export class MailAgent extends Agent<Env> {
  async onEmail(email: AgentEmail): Promise<void> {
    const model = bedrock("us.anthropic.claude-sonnet-4-20250514-v1:0");

    // メール解析
    const rawEmail = await email.getRaw();
    const parsedEmail = await PostalMime.parse(rawEmail);

    // 添付された領収書PDFから必要な情報を抽出する
    const { text: extractedReceiptText } = await generateText({
      model,
      messages: [
        {
          role: "user",
          content: [
            {
              type: "text",
              text: `
      添付された領収書から次の情報を抽出してください：
      - 金額（税込）
      - 税額（わかる場合）
      - 領収日
      - 請求元会社名
      - 領収書番号（わかる場合）
      - 領収内容の説明
      - 適切な経費科目（電車代、資格試験、仮払金、タクシー代）
      日付はYYYY-MM-DD形式で返してください。`,
            },
            {
              type: "file",
              data: firstAttachment.content,
              mediaType: firstAttachment.mimeType,
            },
          ],
        },
      ],
    });

    // 抽出した情報からJSONオブジェクトに変換
    const { object } = await generateObject({
      model,
      schema: receiptDataSchema,
      prompt: extractedReceiptText,
    });

    // Slackに通知を送信
    const { text: slackNotificationText } = await generateText({
      model,
      tools: {
        slackReceiptNotificationTool,
      },
      messages: [
        {
          role: "user",
          content: `以下の領収書データをSlackに通知してください：
            領収書データ: ${JSON.stringify(object, null, 2)}
            送信元メールアドレス: ${parsedEmail.from?.address || "不明"}
            メール件名: ${parsedEmail.subject || "件名なし"}`,
        },
      ],
      toolChoice: "required",
    });
  }
}

		

			
			{
	// 追加
	"durable_objects": {
		"bindings": [
			{
				"name": "MailAgent",
				"class_name": "MailAgent"
			}
		]
	},
	"migrations": [
		{
			"tag": "v1",
			"new_sqlite_classes": [
				"MailAgent"
			]
		}
	]
}

		

			
			import { env } from "cloudflare:workers";
import { tool } from "ai";
import { z } from "zod";

export const slackReceiptNotificationTool = tool({
  description: "領収書データをSlackチャンネルに通知します",
  inputSchema: z.object({
    receiptData: z
      .object({
        amount: z.number().describe("領収金額（税込）"),
        taxAmount: z.number().optional().describe("税額"),
        date: z.string().describe("領収日（YYYY-MM-DD形式）"),
        vendor: z.string().describe("請求元会社名"),
        invoiceNumber: z.string().optional().describe("領収書番号"),
        description: z.string().describe("領収内容の説明"),
        expenseName: z.string().describe("経費科目名"),
      })
      .describe("抽出された領収書データ"),
    emailFrom: z.string().optional().describe("送信元メールアドレス"),
    emailSubject: z.string().optional().describe("メール件名"),
  }),
  execute: async ({ receiptData, emailFrom, emailSubject }) => {
    // 具体的なSlack通知の処理
    const apiToken = env.SLACK_API_TOKEN;
    const channel = "#notify";
    
    // ...

    const response = await fetch("https://slack.com/api/chat.postMessage", {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Authorization: `Bearer ${apiToken}`,
      },
      body: JSON.stringify({
        channel,
        text: message,
        attachments,
      }),
    });

    const data = (await response.json()) as {
      ok: boolean;
      error?: string;
      ts?: string;
    };

    return {
      success: true,
      message: "Notification sent to Slack",
      ts: data.ts,
    };
  },
});