Thread Metadata lost when calling Agent

moret · 2025-04-29T22:06:55.973Z

Hi. I was trying to set a couple of informations to be available at all times to any tool on the Thread Metadata, so I wouldn't need to mirror that information elsewhere. However I noticed that whenever I call an Agent it clears the Metadata field from the Thread. Am I using it correctly, should I use some other way to persist relevant Metadata so I can grab it on any tool?

M

moretOP•4/29/25, 10:11 PM

Here is an example:

import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core";
import { registerApiRoute } from "@mastra/core/server";
import { Memory } from "@mastra/memory";

const memory = new Memory();
const myAgent = new Agent({
  name: "My Agent",
  instructions: "You are a helpful assistant.",
  model: openai("gpt-4o-mini"),
  memory,
});

export const example = registerApiRoute("/example", {
  method: "GET",
  handler: async (c) => {
    const resourceId = "0";
    const threadId = "69868de7-1154-433a-831a-4e14412aadf3";
    const memory = await myAgent.getMemory();
    if (!memory) {
      console.error("/example only works with memory");
      return c.json({ error: "memory not set" }, 500);
    }
    const thread =
      (await memory.getThreadById({ threadId })) ??
      (await memory.createThread({
        threadId,
        resourceId: "0",
        metadata: { foo: "bar" },
      }));
    await myAgent.generate("What can you do?", {
      resourceId,
      threadId,
    });
    return c.json({ thread });
  },
});

import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core";
import { registerApiRoute } from "@mastra/core/server";
import { Memory } from "@mastra/memory";

const memory = new Memory();
const myAgent = new Agent({
  name: "My Agent",
  instructions: "You are a helpful assistant.",
  model: openai("gpt-4o-mini"),
  memory,
});

export const example = registerApiRoute("/example", {
  method: "GET",
  handler: async (c) => {
    const resourceId = "0";
    const threadId = "69868de7-1154-433a-831a-4e14412aadf3";
    const memory = await myAgent.getMemory();
    if (!memory) {
      console.error("/example only works with memory");
      return c.json({ error: "memory not set" }, 500);
    }
    const thread =
      (await memory.getThreadById({ threadId })) ??
      (await memory.createThread({
        threadId,
        resourceId: "0",
        metadata: { foo: "bar" },
      }));
    await myAgent.generate("What can you do?", {
      resourceId,
      threadId,
    });
    return c.json({ thread });
  },
});

import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core";
import { registerApiRoute } from "@mastra/core/server";
import { Memory } from "@mastra/memory";

const memory = new Memory();
const myAgent = new Agent({
  name: "My Agent",
  instructions: "You are a helpful assistant.",
  model: openai("gpt-4o-mini"),
  memory,
});

export const example = registerApiRoute("/example", {
  method: "GET",
  handler: async (c) => {
    const resourceId = "0";
    const threadId = "69868de7-1154-433a-831a-4e14412aadf3";
    const memory = await myAgent.getMemory();
    if (!memory) {
      console.error("/example only works with memory");
      return c.json({ error: "memory not set" }, 500);
    }
    const thread =
      (await memory.getThreadById({ threadId })) ??
      (await memory.createThread({
        threadId,
        resourceId: "0",
        metadata: { foo: "bar" },
      }));
    await myAgent.generate("What can you do?", {
      resourceId,
      threadId,
    });
    return c.json({ thread });
  },
});

import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core";
import { registerApiRoute } from "@mastra/core/server";
import { Memory } from "@mastra/memory";

const memory = new Memory();
const myAgent = new Agent({
  name: "My Agent",
  instructions: "You are a helpful assistant.",
  model: openai("gpt-4o-mini"),
  memory,
});

export const example = registerApiRoute("/example", {
  method: "GET",
  handler: async (c) => {
    const resourceId = "0";
    const threadId = "69868de7-1154-433a-831a-4e14412aadf3";
    const memory = await myAgent.getMemory();
    if (!memory) {
      console.error("/example only works with memory");
      return c.json({ error: "memory not set" }, 500);
    }
    const thread =
      (await memory.getThreadById({ threadId })) ??
      (await memory.createThread({
        threadId,
        resourceId: "0",
        metadata: { foo: "bar" },
      }));
    await myAgent.generate("What can you do?", {
      resourceId,
      threadId,
    });
    return c.json({ thread });
  },
});

When this route is called the first time the answer is:

{
  "thread": {
    "id": "69868de7-1154-433a-831a-4e14412aadf3",
    "title": "New Thread 2025-04-29T22:10:49.814Z",
    "resourceId": "0",
    "createdAt": "2025-04-29T22:10:49.814Z",
    "updatedAt": "2025-04-29T22:10:49.814Z",
    "metadata": {
      "foo": "bar"
    }
  }
}

{
  "thread": {
    "id": "69868de7-1154-433a-831a-4e14412aadf3",
    "title": "New Thread 2025-04-29T22:10:49.814Z",
    "resourceId": "0",
    "createdAt": "2025-04-29T22:10:49.814Z",
    "updatedAt": "2025-04-29T22:10:49.814Z",
    "metadata": {
      "foo": "bar"
    }
  }
}

{
  "thread": {
    "id": "69868de7-1154-433a-831a-4e14412aadf3",
    "title": "New Thread 2025-04-29T22:10:49.814Z",
    "resourceId": "0",
    "createdAt": "2025-04-29T22:10:49.814Z",
    "updatedAt": "2025-04-29T22:10:49.814Z",
    "metadata": {
      "foo": "bar"
    }
  }
}

{
  "thread": {
    "id": "69868de7-1154-433a-831a-4e14412aadf3",
    "title": "New Thread 2025-04-29T22:10:49.814Z",
    "resourceId": "0",
    "createdAt": "2025-04-29T22:10:49.814Z",
    "updatedAt": "2025-04-29T22:10:49.814Z",
    "metadata": {
      "foo": "bar"
    }
  }
}

Then when called again it returns:

{
  "thread": {
    "id": "69868de7-1154-433a-831a-4e14412aadf3",
    "resourceId": "0",
    "title": "Overview of my capabilities and functions",
    "metadata": null,
    "createdAt": "2025-04-29T22:10:53.668Z",
    "updatedAt": "2025-04-29T22:10:53.668Z"
  }
}

{
  "thread": {
    "id": "69868de7-1154-433a-831a-4e14412aadf3",
    "resourceId": "0",
    "title": "Overview of my capabilities and functions",
    "metadata": null,
    "createdAt": "2025-04-29T22:10:53.668Z",
    "updatedAt": "2025-04-29T22:10:53.668Z"
  }
}

{
  "thread": {
    "id": "69868de7-1154-433a-831a-4e14412aadf3",
    "resourceId": "0",
    "title": "Overview of my capabilities and functions",
    "metadata": null,
    "createdAt": "2025-04-29T22:10:53.668Z",
    "updatedAt": "2025-04-29T22:10:53.668Z"
  }
}

{
  "thread": {
    "id": "69868de7-1154-433a-831a-4e14412aadf3",
    "resourceId": "0",
    "title": "Overview of my capabilities and functions",
    "metadata": null,
    "createdAt": "2025-04-29T22:10:53.668Z",
    "updatedAt": "2025-04-29T22:10:53.668Z"
  }
}

N

Nik•5/5/25, 6:21 PM

hi @moret will talk to the team and look into this

A

Abhi Aiyer•5/6/25, 7:31 PM

Hi @moret we are tracking this and will resolve it!

N

Nik•5/9/25, 3:00 PM

hey @moret made a fix for this in this PR: https://github.com/mastra-ai/mastra/pull/4160

should be available in the next alpha release

GitHub

[MASTRA-3367] updated createthread for generatetitle by NikAiyer ·...

Description

This PR ensures that existing thread metadata remains when generating a title for threads.
When setting the generateTitle flag in Memory optons to true, we would upsert a thread with a...

Thread Metadata lost when calling Agent

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