LlamaIndex + MemorySync
LlamaIndex’s Memory with immediate durable persistence, native block recall, and memories as a RAG retriever.
Overview
Install llamaindex-memorysync and pass MemorySyncMemory.from_defaults(user_id=...) to any agent: every user/assistant message persists to MemorySync the moment it happens — not when a 21k-token buffer eventually overflows, the silent-loss trap in block-only integrations — and recalled context injects through the framework’s own memory-block template. A genuine BaseRetriever makes memories RAG-queryable, and five structured tools give agents explicit memory.
Setup status and requirements
- Supported version
- llamaindex-memorysync 1.0.0 (PyPI)
- Last setup review
- 2026-08-23
- Permissions
- A MemorySync API key with read and write scopes; the delete tool needs delete permission.
- Limits
- Requires llama-index-core >=0.13 <0.15 (Python 3.10+). Python only — LlamaIndex.TS has no memory-block architecture to integrate with yet.
Capabilities
- A real Memory subclass — every standard option and block composes
- Immediate persistence on every aput (the waterfall trap, fixed)
- from_defaults works; async-native end to end
- Recall through the native memory-block template with real partial truncation
- MemorySyncRetriever: memories in RetrieverQueryEngine and RetrieverTool
- Five never-raise agent tools with a read-only mode
- Serialization never leaks the API key
Quick Start
from llama_index.core.agent.workflow import FunctionAgentfrom llamaindex_memorysync import MemorySyncMemorymemory = MemorySyncMemory.from_defaults(user_id="customer-7",session_id="thread-42",)agent = FunctionAgent(tools=[...], llm=llm)response = await agent.run("Book my usual trip.", memory=memory)
Use Cases
LlamaIndex agents that remember users across sessions
RAG pipelines that retrieve over user memories
Replacing ephemeral FactExtractionMemoryBlock state with durable storage
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