Letta Quick Reference

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Quick reference for Letta APIs. For detailed documentation, see docs.letta.com.

Installation

pip install letta         # Server
pip install letta-client  # Python SDK

Server

letta server              # Start on :8283

Client

from letta_client import Letta

client = Letta(base_url="http://localhost:8283")

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Common Operations

Agents

# Create
agent = client.agents.create(
    name="my-agent",
    model="openai/gpt-4o-mini",
    embedding="openai/text-embedding-3-small",
    memory_blocks=[
        {"label": "persona", "value": "I am..."},
        {"label": "human", "value": "User info..."},
    ],
)

# List
agents = client.agents.list()

# Get
agent = client.agents.retrieve(agent_id)

# Delete
client.agents.delete(agent_id)

Messages

# Synchronous
response = client.agents.messages.create(
    agent_id=agent.id,
    input="Hello!"
)

# Streaming
with client.agents.messages.stream(
    agent_id=agent.id,
    input="Hello!",
) as stream:
    for chunk in stream:
        print(chunk)

Memory

# Core memory
blocks = client.agents.core_memory.list(agent_id)
client.agents.core_memory.update(agent_id, block_id, value="...")

# Archival memory
client.agents.archival_memory.insert(agent_id, text="...")
results = client.agents.archival_memory.search(agent_id, query="...")

Tools

# Create from function
tool = client.tools.upsert_from_function(func=my_function)

# Attach to agent
client.agents.tools.attach(agent_id, tool_id)

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Model Formats

# LLM models
"openai/gpt-4o-mini"
"anthropic/claude-3-5-sonnet"
"ollama/llama2:7b"

# Embedding models
"openai/text-embedding-3-small"
"letta/letta-free"

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Environment Variables

OPENAI_API_KEY=sk-...
ANTHROPIC_API_KEY=sk-ant-...
LETTA_BASE_URL=http://localhost:8283

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Official Documentation

Topic	Link
Getting Started	docs.letta.com/quickstart
Core Concepts	docs.letta.com/core-concepts
Agent Memory	docs.letta.com/guides/agents/memory
Streaming	docs.letta.com/guides/agents/streaming
Tools	docs.letta.com/guides/agents/tools
REST API	docs.letta.com/api-reference

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Version Compatibility

YouLab requires letta>=0.6.0. Current stable: 0.10.x

See GitHub releases for changelog.

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Related Pages

• Letta Integration - YouLab-specific patterns
• Configuration - Environment setup