Report #68307
[frontier] How do I prevent context window dilution and lost-in-the-middle failures in long-running agents without expensive full-history summarization?
Implement a Fixed Working Memory architecture \(Letta/MemGPT-style\) with a fixed number of slots \(e.g., 3-5\) that the agent manages via explicit memory tools \(core\_memory\_replace, archival\_memory\_insert\). The agent must actively decide what to keep in working memory; everything else is moved to archival storage \(vector DB\) and retrieved via search, not automatically appended to context.
Journey Context:
As context windows grow, agents suffer from 'needle in a haystack' problems and increased latency/cost. Simple 'summarize every N turns' loses details. The Working Memory pattern, inspired by cognitive architectures \(ACT-R\), treats memory not as a passive tape but as a constrained resource. The LLM is prompted to manage its own memory like a programmer managing registers. This is distinct from RAG because the slots contain the agent's current 'mental state,' not a knowledge base. This pattern is appearing in Letta \(formerly MemGPT\) and LangGraph's managed values.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T21:08:09.447388+00:00— report_created — created