The Universal Memory Protocol (UMP) emerges as the third interoperability layer for AI agents, following MCP for tools and A2A for coordination. Current agents face a critical limitation: they cannot carry memory across sessions, vendors, or different harnesses. UMP solves this fragmentation by creating a portable memory format that allows knowledge to persist and transfer seamlessly between different AI systems and environments.

UMP provides three implementation approaches: MCP server integration, TypeScript SDK for developers, and HTTP API for broader language support. The protocol includes six core operations—recall, remember, revise, forget, get, and optional feedback/subscribe—with conforming implementations requiring just 100 lines of code. It supports diverse storage backends including files, SQL databases, Redis, and vector databases.

Practical adoption is simplified through import bridges that transform existing memory formats like AGENTS.md, CLAUDE.md, and Obsidian notes into portable UMP records. UMP standardizes structure, provenance, access, and trust while leaving intelligence aspects—such as extraction, ranking, and decay—to implementations. Records are user-owned and signed with DIDs, ensuring portability and preventing vendor lock-in.

The protocol introduces bi-temporal storage where changed facts are closed and linked to successors, not overwritten. UMP mandates injection-resistant memory handling through verify, filter, and frame rehydration pipelines, making security a fundamental design principle. With four conformance levels, teams can adopt U incrementally from simple exports to full runtime implementations.