Your First Letta Agent

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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 your first 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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    // Memory blocks define what the agent knows about itself and you.
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    // Agents can modify these blocks during conversations using memory
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    // tools like memory_replace, memory_insert, memory_rethink, and memory.
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    memoryBlocks: [
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        {
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            label: "persona",
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            value: "I am a friendly AI assistant here to help you learn about Letta."
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        },
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        {
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            label: "human",
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            value: "Name: User\nFirst interaction: Learning about Letta"
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        }
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    ],
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    // Model configuration
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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}`);

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// Send a message to your agent
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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: [{
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        role: "user",
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        content: "Hello! What's your purpose?"
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    }]
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});
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// Extract and print the assistant's response
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for (const message of response.messages) {
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    if (message.messageType === "assistant_message") {
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        console.log(`Assistant: ${message.content}`);
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    }
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}

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// Send information about yourself
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const response2 = await client.agents.messages.create(agent.id, {
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    messages: [{
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        role: "user",
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        content: "My name is Cameron. Please store this information in your memory."
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    }]
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});
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// Print out tool calls and the assistant's response
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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(`Assistant: ${msg.content}\n`);
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    }
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    if (msg.messageType === "tool_call_message") {
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        console.log(`Tool call: ${msg.toolCall.name}(${JSON.stringify(msg.toolCall.arguments)})`);
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    }
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}

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// Retrieve the agent's current memory blocks
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// API Reference: https://docs.letta.com/api-reference/agents/blocks/list
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const blocks = await client.agents.blocks.list(agent.id);
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console.log("Current Memory:");
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for (const block of blocks) {
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    console.log(`  ${block.label}: ${block.value.length}/${block.limit} chars`);
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    console.log(`  ${block.value}\n`);
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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 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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    const agent = await client.agents.create({
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        name: "hello_world_assistant",
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        memoryBlocks: [
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            {
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                label: "persona",
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                value: "I am a friendly AI assistant here to help you learn about Letta."
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            },
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            {
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                label: "human",
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                value: "Name: User\nFirst interaction: Learning about Letta"
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            }
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        ],
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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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    // Send first message
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    let response = await client.agents.messages.create(agent.id, {
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        messages: [{ role: "user", content: "Hello! What's your purpose?" }]
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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(`Assistant: ${msg.content}\n`);
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        }
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    }
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    // Send information about yourself
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    response = await client.agents.messages.create(agent.id, {
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        messages: [{ role: "user", content: "My name is Cameron. Please store this information in your memory." }]
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    });
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    // Print out tool calls and the assistant's response
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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(`Assistant: ${msg.content}\n`);
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        }
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        if (msg.messageType === "tool_call_message") {
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            console.log(`Tool call: ${msg.toolCall.name}(${JSON.stringify(msg.toolCall.arguments)})`);
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        }
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    }
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    // Inspect memory
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    const blocks = await client.agents.blocks.list(agent.id);
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    console.log("Current Memory:");
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    for (const block of blocks) {
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        console.log(`  ${block.label}: ${block.value.length}/${block.limit} chars`);
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        console.log(`  ${block.value}\n`);
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    }
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}
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main();