Letta Agent SDK

The SDK for stateful agents: create an agent once, then resume it from anywhere. Each agent has its own identity and long-term memory, and keeps both across conversations, models, and the computers it runs on.

Read the documentation for guides and the full API reference.

Quick start

npm install @letta-ai/letta-agent-sdk

import { LettaAgentClient } from "@letta-ai/letta-agent-sdk";

const client = new LettaAgentClient({ backend: "cloud" });

// Create the agent once...
const agentId = await client.createAgent({
  systemPrompt: "You are Nora, a research analyst who tracks our competitors.",
  memfs: true,
});

// ...then resume it, from anywhere, for as long as it lives.
await using session = client.resumeSession(agentId);

await session.send("What changed since last week?");
for await (const message of session.stream()) {
  if (message.type === "assistant") process.stdout.write(message.content);
}

Local and remote management clients can use await using client = new LettaAgentClient(...), or call await client.close() explicitly. Client…