The distinction also makes me think about how information should move between the two layers. Not everything an agent learns during a session deserves to become project memory. A temporary workaround, one-off debugging observation, and an architectural decision have very different lifetimes. A useful pattern could be to treat promotion into project memory as an explicit step: the agent identifies a finding, captures the evidence and scope, and only then proposes it as durable project knowledge. That would reduce the risk of turning every session observation into repository noise while still making important reasoning available to future sessions and teammates.