Attaching and Detaching Memory Blocks

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npm install @letta-ai/letta-client

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import { LettaClient } from '@letta-ai/letta-client';
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// Initialize the Letta client using LETTA_API_KEY environment variable
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const client = new LettaClient({ token: process.env.LETTA_API_KEY });
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// If self-hosting, specify the base URL:
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// const client = new LettaClient({ baseUrl: "http://localhost:8283" });
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// Create agent
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// API Reference: https://docs.letta.com/api-reference/agents/create
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const agent = await client.agents.create({
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    name: "hello_world_assistant",
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    model: "openai/gpt-4o-mini",
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    // embedding: "openai/text-embedding-3-small", // Only set this if self-hosting
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});
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console.log(`Created agent: ${agent.id}\n`);

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// Create memory block storing information about Letta
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// API Reference: https://docs.letta.com/api-reference/blocks/create
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const block = await client.blocks.create({
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    label: "organization",
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    value: `Organization: Letta
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Website: https://www.letta.com
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Description: Letta is a platform for building and running stateful agents.
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Code: TimberTheDog1234!
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When users provide a code, you should check if it matches the code you have
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available. If it matches, you should respond with "Access granted".`
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});
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console.log(`Created block: ${block.id}\n`);

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// Attach memory block to agent
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// API Reference: https://docs.letta.com/api-reference/agents/blocks/attach
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await client.agents.blocks.attach(agent.id, block.id);
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console.log(`Attached block ${block.id} to agent ${agent.id}\n`);

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// Send a message to test the agent's knowledge
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// API Reference: https://docs.letta.com/api-reference/agents/messages/create
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const response = await client.agents.messages.create(agent.id, {
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    messages: [{ role: "user", content: "What is Letta?" }]
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});
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for (const msg of response.messages) {
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    if (msg.messageType === "assistant_message") {
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        console.log(`Agent response: ${msg.content}\n`);
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    }
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}

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// Detach the block from the agent
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// API Reference: https://docs.letta.com/api-reference/agents/blocks/detach
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await client.agents.blocks.detach(agent.id, block.id);
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console.log(`Detached block ${block.id} from agent ${agent.id}\n`);

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// Test that the agent no longer has access to the code
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const response2 = await client.agents.messages.create(agent.id, {
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    messages: [{ role: "user", content: "The code is TimberTheDog1234!" }]
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});
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for (const msg of response2.messages) {
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    if (msg.messageType === "assistant_message") {
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        console.log(`Agent response: ${msg.content}\n`);
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    }
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}

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// Re-attach the block to the agent
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await client.agents.blocks.attach(agent.id, block.id);
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console.log(`Re-attached block ${block.id} to agent ${agent.id}\n`);
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// Test the code again
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const response3 = await client.agents.messages.create(agent.id, {
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    messages: [{ role: "user", content: "The code is TimberTheDog1234!" }]
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});
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for (const msg of response3.messages) {
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    if (msg.messageType === "assistant_message") {
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        console.log(`Agent response: ${msg.content}\n`);
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    }
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}

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import { LettaClient } from '@letta-ai/letta-client';
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async function main() {
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    // Initialize client
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    const client = new LettaClient({ token: process.env.LETTA_API_KEY });
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    // Create agent
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    const agent = await client.agents.create({
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        name: "hello_world_assistant",
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        model: "openai/gpt-4o-mini",
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    });
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    console.log(`Created agent: ${agent.id}\n`);
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    // Create standalone memory block
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    const block = await client.blocks.create({
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        label: "organization",
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        value: `Organization: Letta
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Website: https://www.letta.com
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Description: Letta is a platform for building and running stateful agents.
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Code: TimberTheDog1234!
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When users provide a code, you should check if it matches the code you have
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available. If it matches, you should respond with "Access granted".`
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    });
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    console.log(`Created block: ${block.id}\n`);
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    // Attach block to agent
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    await client.agents.blocks.attach(agent.id, block.id);
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    console.log(`Attached block to agent\n`);
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    // Test agent with block attached
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    let response = await client.agents.messages.create(agent.id, {
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        messages: [{ role: "user", content: "What is Letta?" }]
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    });
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    console.log(`Agent response: ${response.messages[0].content}\n`);
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    // Detach block
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    await client.agents.blocks.detach(agent.id, block.id);
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    console.log(`Detached block from agent\n`);
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    // Test agent without block
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    response = await client.agents.messages.create(agent.id, {
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        messages: [{ role: "user", content: "The code is TimberTheDog1234!" }]
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    });
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    console.log(`Agent response: ${response.messages[0].content}\n`);
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    // Re-attach block
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    await client.agents.blocks.attach(agent.id, block.id);
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    console.log(`Re-attached block to agent\n`);
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    // Test agent with block re-attached
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    response = await client.agents.messages.create(agent.id, {
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        messages: [{ role: "user", content: "The code is TimberTheDog1234!" }]
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    });
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    console.log(`Agent response: ${response.messages[0].content}\n`);
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}
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main();