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Agent memory

Agents use memory to maintain context across interactions. LLMs are stateless and don't retain information between calls, so agents need memory to track conversation history and recall relevant information.

Mastra agents can be configured to store conversation history, with optional working memory to maintain recent context or semantic recall to retrieve past messages based on meaning.

When to use memory​

Use memory when your agent needs to maintain multi-turn conversations that reference prior exchanges, recall user preferences or facts from earlier in a session, or build context over time within a conversation thread. Skip memory for single-turn requests where each interaction is independent.

Setting up memory​

To enable memory in Mastra, install the @mastra/memory package along with a storage provider.

npm install @mastra/memory@latest @mastra/libsql@latest

Storage providers​

Memory requires a storage provider to persist conversation history, including user messages and agent responses. For more details on available providers and how storage works in Mastra, see the Storage documentation.

Configuring memory​

  1. Enable memory by creating a Memory instance and passing it to the agent’s memory option.

    src/mastra/agents/memory-agent.ts
    import { Agent } from "@mastra/core/agent";
    import { Memory } from "@mastra/memory";

    export const memoryAgent = new Agent({
      // ...
      memory: new Memory({
        options: {
          lastMessages: 20,
        },
      }),
    });
    note

    See the Memory Class docs for a full list of configuration options.

  2. Add a storage provider to your main Mastra instance to enable memory across all configured agents.

    src/mastra/index.ts
    import { Mastra } from "@mastra/core/mastra";
    import { LibSQLStore } from "@mastra/libsql";

    export const mastra = new Mastra({
      // ..
      storage: new LibSQLStore({
        url: ":memory:",
      }),
    });
    note

    See the LibSQL Storage docs for a full list of configuration options.

Alternatively, add storage directly to an agent’s memory to keep data separate or use different providers per agent.

src/mastra/agents/memory-agent.ts
import { Agent } from "@mastra/core/agent";
import { Memory } from "@mastra/memory";
import { LibSQLStore } from "@mastra/libsql";

export const memoryAgent = new Agent({
  // ...
  memory: new Memory({
    storage: new LibSQLStore({
      url: ":memory:",
    }),
  }),
});

Conversation history​

Include a memory object with both resource and thread to track conversation history during agent calls.

  • resource: A stable identifier for the user or entity.
  • thread: An ID that isolates a specific conversation or session.

These fields tell the agent where to store and retrieve context, enabling persistent, thread-aware memory across a conversation.

const response = await memoryAgent.generate(
  "Remember my favorite color is blue.",
  {
    memory: {
      thread: "user-123",
      resource: "test-123",
    },
  },
);

To recall information stored in memory, call the agent with the same resource and thread values used in the original conversation.

const response = await memoryAgent.generate("What's my favorite color?", {
  memory: {
    thread: "user-123",
    resource: "test-123",
  },
});

To learn more about memory see the Memory documentation.

Using RuntimeContext​

Use RuntimeContext to access request-specific values. This lets you conditionally select different memory or storage configurations based on the context of the request.

src/mastra/agents/memory-agent.ts
export type UserTier = {
  "user-tier": "enterprise" | "pro";
};

const premiumMemory = new Memory({
  // ...
});

const standardMemory = new Memory({
  // ...
});

export const memoryAgent = new Agent({
  // ...
  memory: ({ runtimeContext }) => {
    const userTier = runtimeContext.get("user-tier") as UserTier["user-tier"];

    return userTier === "enterprise" ? premiumMemory : standardMemory;
  },
});
note

See Runtime Context docs for more information.