Which memory layer should a new agent use?
Under ten sessions of history: none, just the context window. Over ten: the lab's episodic store with summarised recall via the memory adapter. Not a vendor memory product yet.
Tier is not strength
Tier says how much we know. Strength says how hard we are telling you to act. Scored independently.
Machine-readable target
{
"taskType": "multi-session-agent",
"configKey": "agent.memory.store"
}Nothing consumes it yet. Day two: findings ship as defaults into the gateway, routing config and skill library.
Body
As of 21 August 2026: if the agent will hold fewer than ten sessions of history, do not add a memory layer; the context window and the system of record are enough. Above that, use the structured episodic store with summarised recall through the memory adapter (r-memory-layer). Do not adopt either of the two vendor memory layers launched in August as the default; neither documents its consolidation policy, and that is the part that carries the value.
Evidence: x-memory-bench on a 40-session support corpus. Episodic plus summarised recall won on precision by 19 points and on latency by 0.6× above 50k tokens of history (c-agentic-memory-1, c-agentic-memory-2). Graph memory is a special case for entity-heavy workloads and otherwise degrades (c-agentic-memory-3). The vector-store design is in the graveyard as g-vector-memory-v1.
Caveat: no PII in the episodic store until a forgetting mechanism that satisfies APP 11 exists. The two vendor layers are on the Q4 re-bench; this answer may change after that.
What it rests on
Retrieval latency dominates memory-layer cost above ~50k tokens of accumulated history, regardless of store type.
Summarised episodic recall beats raw chunk retrieval on decision-consistency tasks by a wide margin (>15 points).
Graph-structured memory improves entity-heavy tasks and degrades general tasks; it is not a default.
Field
Agentic Memory SystemExperiment · validated
Memory layer bake-off on a 40-session support corpusGraveyard · superseded
Vector-store memory as the agent's long-term memory “Remembered everything, retrieved nothing.”