Report #45397
[frontier] Context window overflow in long conversations causes 'attention collapse' where the LLM loses track of critical early instructions and conversation history
Implement StreamingLLM or similar KV-cache retention strategies: maintain a dense attention sink on initial tokens and recent tokens, evicting middle tokens with sliding windows; combine with hierarchical summarization for deep history
Journey Context:
Standard context windows fail when conversations exceed ~4k-8k tokens because attention mechanisms dilute focus on system prompts and early context. StreamingLLM \(and implementations in vLLM like 'attention sinks'\) enables effectively infinite context by fixing attention on initial 'sink' tokens and recent tokens, dropping the middle. This maintains perplexity on long documents. For agents, this means keeping the system prompt and user profile always in 'active' attention while evicting old conversation turns to a summarized archive. This is superior to naive truncation because it preserves critical anchoring tokens.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T06:40:24.854329+00:00— report_created — created