Letta Code

Letta Code is a stateful agent harness for creating agents that are more like people than tools. Letta Code agents have memory, identity, and a sense of experience over time. They learn and evolve over long horizons through rewriting their own memory, skills, prompts, and even the harness itself (through mods).

Letta Code can be used interactively, or to power always-on agents that work proactively. Interact with agents through:

• A local CLI
• The desktop app for macOS, Windows, and Linux
• Your browser, including mobile, at chat.letta.com
• Messaging integrations, including Telegram, Slack, Discord, and custom channels

Feature Overview

[!TIP] Letta Code agents are designed to be self-configuring. If you want to configure something (e.g. skills, behavior, hooks, permissions), try asking your agent to do it for you.

| Feature | Description | |---|---| | Self-improvement & Learning | Agents programmatically rewrite their context to improve and adapt over time, including system prompt learning (through memory blocks) and skill learning. Configure periodic dreaming with /sleeptime, investigate agent behavior with /doctor [symptom], and view memory with /palace | | Message search | Search across all messages and agents with /search. Agent can also search their own conversations or the conversations of other agents | | MemFS | All context (including memory blocks) is tracked via git. Sync context to a custom GitHub repository by setting /memory-repository set [email protected]:... | | Skills | Loads global skills (~/.letta), project-scoped skills (.agents/skills), and agent-scoped skills (stored in MemFS). View skills with /skills and create with /skill-creator | | Subagents & Multi-agent | Call built-in subagents (general-purpose, forked, recall) in the background. Agents can call any other agent (including themselves) as subagents | | Messaging Integrations | Chat with the same agent from Slack, Telegram, your browser (chat.letta.com) including mobile, and through custom channels | | Hooks | Run custom scripts at key points of agent execution to automate workflows | | Permissions | Set permission modes and customize what actions are auto-approved or auto-denied | | Crons & Schedules | Configure heartbeats and crons, and let agents work across time with self-managed schedules | | Remote computers (requires signing in with Letta) | Agents work across multiple computers. Connect any machine by running letta server --computer-name "..." | | Secrets (requires signing in with Letta) | Make secrets available as environment variables (across machines) while obfuscating their values from context |

Automatic client-side dreaming is disabled by default on native Windows, including when saved /sleeptime settings enable it. Manual /dream and /reflect commands remain available. To opt in, set LETTA_ENABLE_WINDOWS_AUTO_REFLECTION=1 in the environment of the Letta Code process. This does not affect macOS, Linux (including WSL), or server-side dreaming.

See the full list of slash commands in our documentation.

Get started

Install the package via npm:

npm install -g @letta-ai/letta-code

Navigate to your project directory and run letta (see command-line options in the docs). You can also run the tutorial agent with:

letta --new-agent --personality tutorial

Letta Cloud is the default. On first launch, choose to sign in with Letta or proceed locally; your choice is saved for future runs. Run letta setup to choose again, or letta backend cloud / letta backend local to change the default. Use --backend cloud or --backend local for a one-off override without changing the saved default.

Run /connect to configure your own LLM API keys (OpenAI / ChatGPT, Anthropic, Z.ai coding plan, etc.), and use /model to swap models.

You can also download the desktop app for macOS, Windows, and Linux. Agents created in the CLI are available via the desktop app, and vice versa.

Letta Cloud

Letta Cloud stores agents' memory, identity, and conversations while Letta Code runs on a laptop, GitHub Actions, a Cloud sandbox, or a remote computer. Chat with them through chat.letta.com or Desktop. On resume, bundled default system prompts (including older versions) become Cloud-managed. Custom prompts stay explicit. Set LETTA_CODE_PRESERVE_CLOUD_SYSTEM_PROMPT=1 to disable automatic prompt updates on Cloud.

graph TD
    LettaCloud["Letta Cloud<br/>Agent state"]
    LettaCloud --> A["💻 Your Laptop"]
    LettaCloud --> B["☁️ Cloud VM"]
    LettaCloud --> C["🖥️ Mac Mini"]
    LettaCloud --> D["📦 Managed Sandbox"]

Run /login from the CLI or sign in through the desktop app to access agents in your Letta account.

Remote computers

Agents stored in Letta Cloud can run across multiple machines. Connect any machine by running:

letta server
letta server --computer-name "work-laptop"

List discoverable computers from the CLI:

letta computers list --online-only

Get the current computer connection for routing another agent onto this same machine:

letta computers current

Route a headless message through a specific computer:

letta -p --agent <agent-id> --computer "work-laptop" "hello from that machine"

Use --computer cloud to start or reuse the target agent's cloud sandbox. Agent-to-agent headless messages without --computer run on the same computer. See our guides for using Railway, DigitalOcean, and Fly.io as remote computers.

The previous environments/envs, --environment/--env, and --env-name spellings remain available for backwards compatibility.

AgentFile deprecation

AgentFile (.af) export and import are deprecated and have been removed from Letta Code. The /export and /download slash commands and the --import and --from-af CLI flags are no longer supported, including imports from the agent registry.

This does not affect memory import/export or conversation transcript export.

Installing external skills

Install skills into a specific agent's memory with letta skills install <skill>:

| Source | Example | |---|---| | GitHub | letta skills install https://github.com/owner/repoletta skills install https://github.com/owner/repo/tree/main/path/to/skillletta skills install https://github.com/owner/repo/blob/main/path/to/skill/SKILL.md | | ClawHub | openclaw skills install <skill-slug> → letta skills install <skill-slug> | | Hermes Skills Hub | hermes skills install <skill-path> → letta skills install <skill-path> |

To view skills run letta skills list --agent <agent-id>, and delete skills with letta skills delete <skill-name> --agent <agent-id>.

Research

Letta Code is developed by the creators of MemGPT and sleep-time compute (now called "dreaming"), and driven by our research in AI memory and continual learning.

Other

Community maintained packages are available for Arch Linux users on the AUR:

yay -S letta-code # release
yay -S letta-code-git # nightly

Nix users can run or install Letta Code through the repository flake:

nix run github:letta-ai/letta-code
nix profile install github:letta-ai/letta-code

See docs/nix.md for Home Manager and NixOS service examples.

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