ストリーミング構造化ワーキングメモリ

import { Memory } from "@mastra/memory";
import { LibSQLStore } from "@mastra/libsql";
import { z } from "zod";
 
// Define the schema for the todo list
const todoListSchema = z.object({
  items: z.array(
    z.object({
      description: z.string(),
      due: z.string().optional(),
      started: z.string().optional(),
      status: z.enum(["active", "completed"]).default("active"),
    })
  ),
});
 
const memory = new Memory({
  options: {
    lastMessages: 1,
    workingMemory: {
      enabled: true,
      schema: todoListSchema,
    },
  },
  storage: new LibSQLStore({
    url: "file:../mastra.db",
  }),
});

import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
 
const todoAgent = new Agent({
  name: "TODO Agent",
  instructions:
    "You are a helpful todolist AI agent. Maintain the user's todo list as a JSON object according to the provided schema. Each item should include a description, status (active/completed), and optional due/started dates. When the user adds, completes, or updates a task, update the JSON accordingly. Always show the current todo list at the start of the chat.",
  model: openai("gpt-4o-mini"),
  memory,
});

import { randomUUID } from "crypto";
import { maskStreamTags } from "@mastra/core/utils";
 
// 会話を開始
const threadId = randomUUID();
const resourceId = "SOME_USER_ID";
 
// 新しいtodoアイテムを追加
const response = await todoAgent.stream(
  "Add a task: Build a new feature for our app. It should take about 2 hours and needs to be done by next Friday.",
  {
    threadId,
    resourceId,
  },
);
 
// ストリームを処理し、ワーキングメモリの更新を隠す
for await (const chunk of maskStreamTags(
  response.textStream,
  "working_memory",
)) {
  process.stdout.write(chunk);
}

// UIフィードバックを提供するためのライフサイクルフックを追加
const maskedStream = maskStreamTags(response.textStream, "working_memory", {
  // working_memoryタグが開始されたときに呼び出される
  onStart: () => showLoadingSpinner("Updating todo list..."),
  // working_memoryタグが終了したときに呼び出される
  onEnd: () => hideLoadingSpinner(),
  // マスクされたコンテンツと共に呼び出される
  onMask: (chunk) => console.debug("Updated todo list:", chunk),
});
 
// マスクされたストリームを処理
for await (const chunk of maskedStream) {
  process.stdout.write(chunk);
}

{
  "items": [
    {
      "description": "Buy groceries",
      "due": "2025-07-01",
      "started": "2025-06-24",
      "status": "active"
    },
    {
      "description": "Finish project report",
      "due": "2025-07-05",
      "status": "completed"
    }
  ]
}