Memory is how Xema gives agents durable, scoped context without re-uploading every prompt. Each memory node is typed, scoped to a space — memory owns system, org, project and user — and carries provenance (writtenBy, writtenAt, digest). Agents recall memory through the memory:recall@1 capability (exposed to the shell as shell:memory.recall@1) — never through raw blob reads — so every recall is audited and gated. Digest gates keep writes cheap: a maintenance pass on an unchanged node consumes zero tokens.