Letta MCP Server
Official Letta MCP server enabling AI agents to interact with Letta (formerly MemGPT) — the stateful agent framework with persistent memory management — creating and managing Letta agents, accessing long-term memory stores, adding and searching memories, running stateful agent conversations, and integrating Letta's memory-augmented agent infrastructure into MCP-based workflows.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
HTTPS for Cloud. API key auth. Memory data may be sensitive — review retention. Official Letta MCP.
⚡ Reliability
Best When
An agent needs to interact with Letta's stateful memory infrastructure — for building memory-augmented assistants, managing persistent agent state, or integrating MemGPT-style memory into larger agent systems.
Avoid When
You need simple stateless LLM calls or don't have a Letta server running — the overhead isn't worthwhile for short-lived agent tasks.
Use Cases
- • Creating persistent stateful agents with long-term memory from agent orchestration systems
- • Querying and updating agent memory stores from memory management agents
- • Building memory-augmented AI assistants from personal assistant agents
- • Running Letta agents as sub-agents in larger MCP-based systems from orchestration agents
- • Integrating MemGPT-style memory management into existing agent workflows from migration agents
- • Managing multiple stateful agent personas from agent management agents
Not For
- • Simple stateless LLM calls (use direct LLM MCPs for stateless queries)
- • Teams without Letta server deployed (requires local or cloud Letta instance)
- • Short-lived agents where memory persistence adds unnecessary overhead
Interface
Authentication
Letta API key required for Letta Cloud; local Letta server may not require auth. LETTA_BASE_URL configures endpoint. Self-hosted Letta is also supported.
Pricing
Letta is open source — self-hosted is completely free. Letta Cloud offers managed hosting with a free tier. MCP server is free.
Agent Metadata
Known Gotchas
- ⚠ Letta server (local or Cloud) must be running and accessible before MCP can connect
- ⚠ Letta renamed from MemGPT — some docs and examples still use old MemGPT naming
- ⚠ Agent and memory management can be complex — Letta's stateful architecture has learning curve
- ⚠ Memory search quality depends on embedding model configured in Letta
- ⚠ Official Letta MCP but Letta is a fast-moving project — API may evolve significantly
- ⚠ Self-hosted Letta requires LLM provider API keys (OpenAI, Anthropic, etc.) configured separately
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Letta MCP Server.
Scores are editorial opinions as of 2026-03-06.