Design Patterns for Long-Term Memory in LLM-Powered Architectures

LLMs face a fundamental limitation: conversational amnesia due to stateless design and finite context windows. Four architectural patterns have emerged to solve long-term memory: MemGPT virtualizes context like an OS managing RAM/disk; OpenAI provides global, automated personalization across all chats; Claude enforces project-scoped isolation with manual curation; and toolkits like LangChain/Autogen offer composable primitives for custom solutions. The industry is shifting from unstructured RAG toward autonomous memory orchestration, knowledge graphs for relational reasoning, and multi-agent pipelines with strict typing and audit capabilities.