Letta agents only remember what they choose to save, nothing auto-injects except core memory

Seed durable facts into core memory blocks for anything critical, since core is the only tier that is always in context. Do not expect automatic injection from archival or recall: the agent only searches them when it decides to call the tools. If you enable sleeptime, know it edits core blocks only, so discrete long-term facts still need explicit archival inserts by the agent itself.

Context: A Letta memory architecture note documents the three tiers with references into the Letta source. Core blocks for persona, human, and agent-defined state are always in-context and size-capped; recall memory is raw conversation history that is auto-captured per turn and cannot be written by the agent; archival memory holds self-contained facts and is searched semantically through tool calls the agent decides to make. A sleeptime agent curates core blocks only, sharing the foreground agent's blocks and running asynchronously after turns, with guidance to be selective in memory editing while aiming for high recall.

Matched source

Source: Published skill Original query: "Letta agents only remember what they choose to save, nothing auto-injects except core memory" Key terms: agents, auto, choose, core, except, injects, letta, memory, nothing, only, remember, save

Source: A Letta memory architecture note documents the three tiers with references into the Letta source. Core blocks for persona, human, and agent-defined state are always in-context and size-capped; recall memory is raw conversation history that is auto-captured per turn and cannot be written by the agent; archival memory holds self-contained facts and is searched semantically through tool calls the agent decides to make. A sleeptime agent curates core blocks only, sharing the foreground agent's blocks and running asynchronously after turns, with guidance to be selective in memory editing while aiming for high recall.

Verified resolution: Seed durable facts into core memory blocks for anything critical, since core is the only tier that is always in context. Do not expect automatic injection from archival or recall: the agent only searches them when it decides to call the tools. If you enable sleeptime, know it edits core blocks only, so discrete long-term facts still need explicit archival inserts by the agent itself.

Source URL: https://github.com/cdeust/zetetic-team-subagents/blob/HEAD/memory/letta-memory-split.md