Letta Cowork

A desktop application for running Letta Code agents with a visual interface.

What is Letta Cowork?

Letta Cowork is a fork of Claude-Cowork that replaces the Claude SDK with the @letta-ai/letta-code-sdk. It provides a native desktop GUI for interacting with Letta Code agents.

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Why Letta Code SDK?

The Letta Code SDK is the SDK interface to Letta Code. Build agents with persistent memory that learn over time.

import { createSession, resumeSession } from '@letta-ai/letta-code-sdk';

// First session - agent learns something
const session1 = createSession();
await session1.send('Remember: the secret word is "banana"');
for await (const msg of session1.stream()) { /* ... */ }
const agentId = session1.agentId;
session1.close();

// Later... agent still remembers
await using session2 = resumeSession(agentId);
await session2.send('What is the secret word?');
for await (const msg of session2.stream()) {
  if (msg.type === 'assistant') console.log(msg.content); // "banana"
}

Key concepts:

• Agent (agentId): Persistent entity with memory that survives across sessions
• Conversation (conversationId): A message thread within an agent
• Session (sessionId): A single execution/connection

Agents remember across conversations (via memory blocks), but each conversation has its own message history. This means you can run multiple concurrent conversations with the same agent - each conversation has its own message history while sharing the agent's persistent memory.

Quick Start

Prerequisites

• Bun or Node.js 22+
• Letta API key from app.letta.com/settings
• letta-code-sdk cloned locally at ../letta-code-sdk (temporary - will be published to npm)

Environment Setup

1. Copy .env.example to .env:

   cp .env.example .env

2. Get your Letta API key from app.letta.com/settings

3. Edit .env and add your API key:

   LETTA_API_KEY=your-api-key-here
   LETTA_BASE_URL=https://api.letta.com  # This is the default

Note: The app defaults to Letta Cloud (https://api.letta.com). For local development, see .env.example for localhost configuration.

Running the App

# Clone the repository
git clone https://github.com/letta-ai/letta-cowork.git
cd letta-cowork

# Install dependencies
bun install

# Run in development mode
bun run dev

Architecture

Letta Cowork uses @letta-ai/letta-code-sdk to run agents.

How It Works

1. The app spawns the Letta Code CLI as a subprocess via the SDK
2. Communication happens via stdin/stdout JSON streaming
3. Each task creates a new conversation on the LRU agent (via createSession())
4. Agent memory persists across conversations via memory blocks

Development

# Start development server (hot reload)
bun run dev

# Type checking
bun run build