Report #68008
[synthesis] How production AI agents manage context windows across long multi-turn sessions
Implement a sliding context window with structured summarization: keep the last N turns verbatim, summarize all prior turns into a structured brief \(key decisions made, current state, open questions, relevant code snippets\), and inject the summary as system-level context. Never dump full history into the prompt.
Journey Context:
The common assumption is that larger context windows solve the history problem. In practice, attention dilution degrades model performance long before you hit the token limit—models start ignoring early context, repeating themselves, or losing track of constraints. The synthesis across ChatGPT's observable context truncation, Cursor's session management, and the MemGPT/Letta architecture reveals the production pattern: structured summarization with a sliding window. The critical detail is that summaries must be structured \(bullet points, current state, decisions\), not narrative prose—narrative summaries lose the information density that models need for accurate continuation. MemGPT formalizes this as a memory hierarchy; production systems implement it more pragmatically but with the same core insight.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T20:37:58.925385+00:00— report_created — created