MemoryLake
Engineering & Developermemory eviction strategy for long-running agents

Manage Long-Running Agent Memory With Eviction That Preserves What Matters

Long-running agents accumulate memory until retrieval slows or storage explodes. Naive eviction (drop oldest) loses critical context. MemoryLake provides typed eviction strategies — preserve verified facts, archive stale events, promote durable skills — so memory stays useful at scale.

Day 1“Long-running agents accumulate memory until retrieval slows”“or storage explodes.”✓ Got it, I will remember.Day 7 — new session“Same task again — can you keep the context?”× Sure — what was the context again?(forgot every detail you taught it)+ MEMORYLAKE LAYERMemory auto-loadedPer-type retention rulesImportance-weighted retentionCold archive instead of deletionSESSION OUTPUT✓ Same prompt, on-brand answerNo re-briefing required.

Manage Long-Running Agent Memory With Eviction That Preserves What Matters

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The problem: naive eviction loses what matters

The agent has been running for six months. There's too much memory now. Dropping oldest entries loses founding decisions. Dropping least-accessed loses critical-but-rare facts. Without typed eviction, long-running agents either grind to a halt or amnesiac themselves.

How MemoryLake handles long-running memory eviction

Per-type retention rules

Per-type retention rules

Facts retained longer than ephemeral chat turns; reflections promote to skills.

MEMORYImportance-weighted rete…

Importance-weighted retention

Memory used in successful decisions stays; never-retrieved entries archive.

MEMORYCold archive instead of deletion

Cold archive instead of deletion

Old memory archived; available on demand, not in active retrieval.

Audit trail on eviction

Audit trail on eviction

Compliance can confirm what stayed and what archived.

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How it works for memory eviction

  1. Connect — Configure retention rules per memory type.
  2. Structure — Memory tagged by type and importance on write.
  3. Reuse — Active retrieval pulls fresh memory; archive available for deep queries.

Before vs. after: long-running agent memory management

Naive evictionMemoryLake eviction
Retention policyDrop oldestPer-type with importance
Critical-but-rare fact retentionOften lostPreserved
Storage growthUnbounded or lossyBounded with archive
Audit "what got dropped?"NoneEviction log

Who this is for

Engineering teams running agents that operate for months or years per user — copilots, assistants, agentic systems — where memory accumulation has become an architectural concern.

Runnable demoabout 2 minutes

Try this use case on your own account

An ops agent has run for six months and remembered 36 things; its active memory is capped at 20. Drop the oldest and it loses the founding ledger rule. Drop the least used and it loses the quarter-end freeze it needed once. Each loss shows up weeks later, as a task the agent goes ahead with because nothing in its memory says not to.

What you will see

  • 36 memory entries pinned word for word (6 decisions, 4 constraints, 4 preferences, 16 events, 6 chat turns), each with type, written on, use count and last used in metadata — what an eviction job reads
  • Three policies over the same metadata, each keeping 20 in its own project: drop-oldest evicts the ledger rule, drop-least-used evicts the quarter-end close freeze, typed retention keeps every decision, constraint and preference and only events still in use
  • The same three tasks searched against all three active memories (top 8): the 29 December migration misses the freeze under drop-least-used, the ledger fix misses the append-only rule under drop-oldest, typed retention 3 of 3; the control task is found everywhere
  • Typed retention moves its 16 to a cold-archive project with an eviction record (when, policy, reason, original fact id); search --projects active,archive answers an old-incident question at #1 that the active memory alone cannot. Plus check, evictions and a local web UI

You need: a MemoryLake API key · the memorylake CLI · Python 3.9+

Run it

git clone https://github.com/memorylake-ai/memorylake-usecases.git
cd memorylake-usecases/eviction-memory
export MEMORYLAKE_API_KEY=sk-…
python3 demo.py          # or: python3 web/server.py

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Related use cases

Frequently asked questions

Can archived memory be retrieved?

Yes — slower path, but available.

Configurable retention windows?

Yes, per memory type and scope.

Self-host?

Yes — enterprise tier deploys in your VPC.